134

Chapter – 9: Methods for Preservation of Insects

Insects might be preserved using different means and/ or techniques. Size of

the insect and degree of body sclerotization are factors that determine the

method to be employed for the insects of the different orders. In all the

museums surveyed, the one common technique of preserving insects is by

directly pinning them. In order to preserve the insects in this manner, usually

the best time is soon alter their death, while they are still soft, for it is easier to

pin and manipulate. If this is not possible to be done due to any reason, (insect

has dried out or was placed in alcohol or any other fluid for fixation or killing)

then the insect(s) should be temporarily stored. Once the time comes to pin the

insects, they are brought out from their temporary storage. At this time if the

insects are found to have become too rigid or contrarily, too fragile, it is always

a better idea to relax them, by subjecting them to a damp atmosphere in a high

humidity chamber.

Relaxing Insects Insects might be relaxed using several techniques. Preparing a relaxing jar or

chamber may be of following ways. By putting moist cotton at the bottom of an

air tight container, the cotton is then covered with an aluminium foil, on which

the insect is placed and the container is closed. 1 to 2 days should be

sufficient, but no longer than a week is allowed, as it may mould. By using any

tightly sealed container like a plastic box, large jar or rubberized box provided

with a moistened paper towel. Any type of antiseptic agent or Lyzol or specialty

products such as Glanz relaxing fluid or chloro-cresol, should be added into the

container used to prevent the growth of fungi and moulds. Cochrane, 2006, (p.

43.) has referred to using a special fluid namely, Brenda May beetle relaxing

fluid, although, used for relaxing beetles specifically. It has the composition of

96% Ethyl alcohol 265 ml, Water 245 ml, Ethyl Acetate 95 ml and Benzene 35

ml. Another is Barber’s relaxing fluid, which can relax beetles, grasshoppers,

crickets, bugs, flies, and some wasps, by soaking such insects in this fluid for

half an hour. “Particular body parts, like legs, may be “softened” independently

using a drop of Barber’s fuid ...” (Obyoski, 2007, p.3.), which is a mixture of

95% ethanol 1000 ml, distilled water 1000 ml, ethyl acetate 375 ml and

135

benzene 125 ml (Millar, Uys & Urban, 2000, p. 64.). Ethyl acetate or phenol

might prevent mould as well. By placing on damp paper towel in sealed glass

or plastic container (like petri-dishes); the insects are left overnight or longer

(large-bodied insects) and checked periodically by flexing a leg. Insect

Collection Guide (2013) states that “… a paper towel soaked with water then

rung out works well, but do not let the insects touch the paper towel as this may

cause setae or scales to mat.” (p. 5.). “The insect specimens should be laid on

metal screen or a piece of cardboard cut to fit the container, rather than directly

in contact with the wet paper towelling or sand.” (Knausenberger, 1986, p. 18.).

“A piece of fine plastic flyscreen should be placed on the sand, supported on

three or four small wooden blocks so that it will not come in direct contact with

the wet sand.” (Hangay and Dingley, 1985, p.126.). Lysyk (1995) suggested the

use of a relaxing box with a piece of soft wood that fits inside at the bottom of

the container. A little water containing a few drops of ethyl acetate is poured

underneath the wood at the time of use. Glass desiccators, with water in the

base also serve the purpose. Millar, Uys, and Urban (2000, p. 63.) suggest that

a thymol or phenol crystal or a few drops of ‘Dettol’ or ‘Milton’ might be added

to the water in the desiccator to act as the fungicide. Beside the use of relaxing

jar/ box/ dishes, one can resort to many other techniques to relax the insects

collected or obtained by a museum like, the dead moths might be relaxed

inside a plastic container containing a few freshly chopped laurel leaves;

soaking in alcohol might be useful in relaxing hard bodied insects; steaming the

beetles to relax them – kept confined inside paper containers during the

steaming, minimizes vapour condensation on the specimens and keeps intact

delicate pubescence; Coleoptera specimens might also be relaxed by being

boiled in water or by being dropped in near boiling water; large moths and

butterflies can be relaxed by injecting hot water into the thorax; a 10% solution

of ammonia, also serve the purpose; in case of insects belonging to other

orders, the ammonia solution or hot water is injected into the wing muscles with

a very fine syringe; Coleoptera specimens might also be relaxed by being

immersed in or by being subjected to the vapour of wood naptha in a confined

space, to relax them; besides this, equal parts of wood naptha and alcohol

mixed with a few drops of carbolic acid, might also be used as the relaxant.

Insect specimens might be rehydrated by being soaked in Decon 90 (or similar

surface active agent) for 16 hours, according to Upton and Norris, 1980, as

136

reported by Cochrane, 2006, p. 45.). To complete the process, the specimens

should be thoroughly rinsed and immersed in water. 10% acetic acid might be

used to soak the insects to be relaxed. After sufficient time (may be three to

four weeks as suggested by Hangay and Dingley, 1985, p.126.), the acid

should be rinsed out with distilled water, and dried on blotting paper. Soaking

insects in a solution of water to which a little detergent has been added, or a

solution of 0.5% trisodium phosphate (for a day) or in a 2% aqueous solution of

carbolic acid; might also relax the insects. Insects to be relaxed might be left

inside a microwave, set at a high temperature for a short span of 10 to 15

seconds. Ken Chan (2010, Relaxing and Stuffing Section) suggests “A steam

bath set at around 45ºC (113ºF) can relax insects within 2-3 hours …”

At the Government Museum, Chennai, the personnel introduce the killed

insects into a relaxing chamber. They apply two methods to prepare this

relaxing jar. In one, they use a few crystals of para-dichloro-benzene, while

moist sand is used in the other. 6 to 7 hours, is considered sufficient to relax

the insect(s) completely, in either of the relaxing jars used. The personnel at

the Bombay Natural History Society, Mumbai reported the researcher that they

use ethyl acetate inside the relaxing jar, used for the insects. Whereas, the

taxidermist of the Bengal Natural History Museum, Darjeeling told the

researcher about the use of carbolic acid (phenol) inside the relaxing jar, used

for insects in their museum (Plate 9.1). The Indian Museum, Kolkata prefers the

use of relaxing dishes. The personnel at the Zoological Survey of India

(custodian of the insects in the collection of the Indian Museum), place the

insects individually in petri-dishes, each of which contain a blotting paper

moistened with a few drops of water. Each of the petri-dish is covered with

another one and the setup is allowed to remain in this way for a day. This

allows time required to dampen the insect, softening them making spreading

and pinning them easier. This is exactly the set up used, by the Coleoptera

Section of the Zoological Survey of India in Kolkata. Some entomologists

suggest the use of a flat plastic container with an airtight lid as the relaxing

dish. The Insectary – a part of the Entomology Museum at the Forest Research

Institute, Dehradun had desiccators but whether used for relaxing insects is not

known. (Plate 9.2) The Orthoptera Section of the Zoological Survey of India,

Kolkata uses carboxylic acid solution, as the relaxing fluid. The amount of time

137

for which the insects should remain in the chamber to be completely relaxed,

will depend on the age of the collection (i.e., the time gap between the day of

collection and the day they are being subjected to relaxation). (Plate 9.3)

Cleaning and/ Degreasing Insects

Some entomological specimens might have to be washed clean, before being

finally mounted. Insects collected in ethylene glycol using a pitfall trap, should

be washed thoroughly, on a dense cloth sieve under running water. Insect

specimens collected in alcohol, using Berlese funnel or Moczarsky-Winkler

selector or ground traps or with any equipment that is used in any aquatic

habitat; are often contaminated with soil particles and debris. A floating process

is applied in such cases.

A saturated solution (NaCl) is prepared. The raw samples are

drained and transferred into 96% ethanol. After 24 hours the

samples are transferred into tall cylinder glasses ... The alcohol

is drained from the samples, and the cylinder, held in a tilted

position, filled with the saturated solution. Soil particles stay in

the bottom of the cylinder and all organic matter floats ... Open

entities such as decaying plant particles … start to sediment

immediately whereas closed entities such as arthropods … float

longer. Without stirring it, the solution can be left for a few

minutes to allow further sedimentation of debris ... The floating

layer can be poured with a swift movement onto a dense cloth-

sieve, rinsed thoroughly under running water, blotted, and

transferred into 75% ethanol. (Hangay and Dingley, 1985, pp.

127-128.).

Depending on the order to which the insects belong, the cleaning techniques

might vary. For example, solid matter, scales, pollen dust, if present on the

insects of the Order Lepidoptera, might be picked off with a small camel-hair

brush, taking great care, but if present on beetles (Order Coleoptera), the

insects might be gently scrubbed with water or weak alcohol to loosen up the

particulate matter, safely under a binocular microscope, and if present on very

fragile insects (dry and rigid), they are required to be immersed in a fluid.

138

Depending on the matter to be removed from the insect’s body, techniques will

be different. “Just plain dirt, dust and grime are best removed in water, to which

one of the synthetic detergents (such as ‘Tide’, ‘Surf’, ‘Daz’) has been added.”

(Browne, 1927, p. 98.). A soft brush (size 0 or 1) used under the low power of a

binocular microscope, or, a fine jet of water from a glass pipette, will surely

remove such adhering particles from the insects. Specimens greasy due to

oozing out of their fat material or oil content require an organic solvent to

degrease them. Soaking for a period of time in ethyl acetate or benzene or

ether or alcohol or white gasoline (Coleman ® Stove Fuel), proves useful.

Mouldy or fungus affected specimens can be cleaned using a paint brush

dipped in phenol (carbolic acid). Chloroform or ethyl acetate might also be

used.

The researcher did not come across this step in the curation of insects, in any

of the museums visited, except at the Isoptera Section of the Zoological Survey

of India (Kolkata).

Mounting Insects

Insect collection might be mounted in one of the following ways for permanent

preservation.

Direct pinning with insects pins -

This is the most common method resorted to, when wanting to preserve the

insects dry. Almost all the museums surveyed, preserve most of their

entomological specimens in this way.

Two important requirements in preserving insects thus, are a pinning block and

insect (entomological) pins. The usual material used for constructing a pinning

block is wood. Fohrer (n.d) suggests the use of an aluminium pinning block.

Considering the varied sources, the dimension of pinning block range

accordingly, approximately 7.5 cm (3 in.) X 2.5 cm (1 in.). A pinning block has

three blocks of different heights. The pinning block can be constructed out of

the single piece of wood or using three blocks of wood the required

dimensions, glued together. The centre of each such block (step) should have

a hole drilled all the way through it, the diameter of which should be large

enough for the head of the entomological pin to slip through. It is suggested to

139

be 0.16 cm approximately (Lysyk 1995, revision of Mc Mullen, 1965) but nearly

double, i.e., 0.062 cm (1/32 in) by Knausenberger, 1986 (p. 10.). Pinning block

is used, once the insect has been pinned at the appropriate position, on its

body. The head of the entomological pin should be placed at the central hole of

the first or the third step of the block (i.e., either the highest or the lowest one),

as both these steps are used to position insects at the correct height on the

pins. Pushing the pin through the insect into the hole of the step of the pinning

block, moves the insect to the height on the pin it should be, which is almost

near the head of the pin. “However, it is better to have the top of each insect a

standard distance (usually 1.0 cm) from the top of each pin rather than the

bottom of each insect a standard distance from the point of the pin.” (Lysyk,

1995, revision of Mc Mullen, 1965, p.7.). Of all the museums visited by the

researcher, only the Regional Museum of Natural History in Bhubaneswar,

specified that 2/3rd of the pin should remain above the insect, which is about 8-

10 mm. This allows the pin to be picked up with hand, without touching and/

breaking the insect or its parts. Besides providing ease in handling, a pinning

block brings about uniformity in pinning height, imparting, a neatness in the

appearance of the collection. (Picture 9.1)

All the museums surveyed during the research work, stressed on the use of a

special kind of pin, for the direct pinning of insects. Entomological pins might be

categorized into two types – ‘English’ and ‘Continental’. The British or English

pins are stainless steel pins, whose heads are made up of the same material

as the pins. The English pins, brass plated with heads, are also popular. The

range they offer not only in terms of length but thickness as well is an

advantage, but the lack of uniformity in numbering is a disadvantage as it leads

to confusion. According to Hangay and Dingley, (1985), “The most popular

thickness (approximately) are 0.34 mm, 0.38 mm, 0.43 mm, 0.46 mm, 0.50

mm, 0.59 mm, 0.66 mm, 0.70 mm and 0.78 mm. The best length to use is 34

mm, since these pins will fit in most insect boxes.” (p.128). Pins of other length

and thickness, are also available. The size of the insect determines the length

and the thickness to be used. Recommended by most, the continental pins

might be either black (being made up of ordinary spring steel) or silver (being

made of stainless steel) or of a blued or a lacquered (japanned) finish; stainless

steel is the best option when considering the material because they are rust

140

proof. It has a small round head. The continental pin has a separate head that

is not a moulded part of the shaft. “These either pull off with a jerk, leaving the

pin now thin and headless, or push right down the shaft.” (Browne, 1927, p.

111) According to Schauff (2005, revised 1986) nylon is the commonly used

material for the pin heads, these days.

Pins of Nos. 2 and 3 are generally used by most of the museums because

these sizes are suitable for most of the insects, not only in terms of pinning, but

handling the specimens as well. Thinner pins of sizes 000 to 1 might be used,

but for very small insects. Sizes 4 to 7 and above are used for insects

increasing in size. Of all the museums having a collection of insects, only

Bombay Natural History Society, Mumbai has shown the entire lot of the

entomological pins, used by the Society to pin its specimens. Here Nos. 00 to 5

and Nos. 12 and 16, were shown. The Orthoptera Section of the Zoological

Survey of India in Kolkata also showed similar entomological pins, from Nos. 0

to 5. (Plates 9.4 and 9.5)

Position of Pinning Insects of Different Orders

Not at all insects are possible to be preserved dry by direct pinning, in the same

manner. “The insertion point for the pin may very slightly depending on the type

of insect.” (Chan, 2010, Mounting and pinning section). Pinning is always done

through the thorax (may be meta but usually meso-thorax), i.e., just off the

centre towards the right. Bees, wasps (and others of the order Hymenoptera);

flies (and others of the order Diptera); Odonates (dragonflies and damselflies)

and many other insects, are pinned through the thorax between or slightly

behind the bases of the fore wings, to the right of the midline as well. Wings are

usually turned upwards or sidewise from body, but in a manner to allow visibility

of the venation. If crumpled, the wings might be straightened using a camels

hair brush dipped in 70 percent alcohol (in case of Diptera) or Peterson’s XA

mixture (in case of Hymenoptera). True bugs should be pinned submedially,

through the right corner of the triangular scutellum (posterior portion of either

the mesonotum or the metanotum of an insects thorax), between the bases of

the front wings. Grasshoppers (and other insects of the order Orthoptera)

should be pinned through the back of the pronotum/ prothorax (the saddle-

shaped structure of the thorax just behind the head) to the right of midline, such

141

that the pin emerges between the middle and the hind legs of the right side.

Beetles (Order Coleoptera), earwigs (Order Dermaptera) and large hoppers

(Order Hemiptera) should be pinned through the right forewing (elytron in case

of the beetles, which is the hard upper wing cover), about halfway between the

two ends of the body. Thus, the pins should pass through the methathorax and

emerge through the metasternum (on the underside), between the middle and

the hind legs on the right side. Usually, the Lepidoptera (butterflies and moths)

and the larger Odonates, are pinned, through the middle of the mesothorax at

the thickest point or just behind the base of the forewings. Unlike, insects of the

orders Orthoptera and Coleoptera, etc. the wings of Lepidoptera and the larger

Odonata should be properly spread out. Moreover, except the insects of the

order Orthoptera (locusts, grasshoppers, crickets, etc.), these methods are

same as most of the orders, which are pinned differently by the two museums,

the Indian Museum, Kolkata and the Govt. Museum, Chennai. If the wings are

spread out, they are pinned in the middle between the bases on the wings. In

case, the wings are not spread out, the pin should pass through the right wing.

The wings of the Lepidoptera and the other larger insects, having a wing span

of more than an inch, need to be to properly spread out. To serve the purpose

what is required is a spreading board also known as the setting board, or the

mounting board. A spreading board might be made up of different materials like

masonite board, soft wood such as balsa wood, styrofoam or any normal wood.

Balsa wood or any other soft wood or styrofoam or polystyrene if used, then the

spreading board will not require any other material to be fitted into its groove, or

on the sides (top pieces/ slats), because pin easily goes through such material.

If normal wood is used to construct a spreading board, then the groove of such

boards should be made up of cork material or soft wall board or as mentioned

earlier styrofoam or soft wood or balsa wood or polystyrene. According to

Hangay and Dingley, (1985): “ … to assure perfect symmetry and uniformity,

setting boards of various sizes are used.” (p. 135.). Some easy constructions of

spreading boards include a block of balsa wood 6 X 6 X 2 inches with a slot of

0.5 to 1 inch deep in one face of the block. (Scheibner, 1982, revised by Neel,

2000, p.15). It is also suitable to use polyurethane blocks as the material for the

spreading board. Such boards and the well-known English boards are suitable

for setting insects desired, with their wings perfectly horizontal. The wings of

the specimen may sag due to humidity, when such boards are used. Nailing

142

two slots of soft wood – 30 cm long, 5 cm wide and 0.6 cm thick to two blocks

of wood – 13 cm by 5 cm by 1.2 cm (one block at each end) and leaving an

even gap of 0.6 cm between the long slats of wood, makes a spreading board.

A piece of thick composition cork material or soft wall board 30 cm by 5 cm,

nailed or glued beneath the crack between the two long wooden slots,

completes the construction. (Mc Mullen (1965) revised by Lysyk (1995), p. 8.).

Well-known European boards which have wing supporting slats sloping slightly

away from the central groove, set the specimens’ wings on a slight angle.

Hangay and Dingley, 1985 opine, “If sagging occurs at all, it is of a much lesser

degree than that of horizontally set wings. It is more pleasing aesthetically,

since live insects, especially butterflies, tend to spread their wings with a

slightly upward angle.”(p.136.). Some entomologists feel, that the mounting

board should have about 150 degrees of angle from one surface to the other.

Millar, Uys and Urban (2000, p.68.) also supported the use of angled setting

boards for Lepidoptera.

The Indian museum, in Kolkata stresses on the fact that the board should be

made of soft material, in order to allow the penetration of pin into it. Although

the Government Museum, Chennai, informed that the mounting board should

be made up of two cork sheets, which should be adjustable according to the

size or the body of the insect. But, the spreading board they showed seemed to

be different. Although, this one is adjustable (a screw being present for the

purpose), the insect spreading board is basically wooden with a styrofoam

lining in the central groove. The top pieces on either side, is also of Styrofoam.

(Plate 9.6) Pin sizes normally used are 3 and 4. For proper stretching, a

stretching board with adjustable screws is used, at the Orthoptera Section,

Zoological Survey of India, Kolkata. Made up of hard wood, it has a lining of

soft wood to allow pins to be inserted into it. (Plates 9.7 and 9.8) The Regional

Museum of Natural History, Bhubaneswar does not use the adjustable type of

spreading board. Insect spreading board with a fixed diameter is used here.

Rectangular thermocol blocks were seen to be used for pinning and stretching

insects at the museum. (Plate 9.9) The Bombay Natural History Society,

Mumbai, uses a spreading board provided with screws for adjustment and

styrofoam sheets as top pieces and for lining of the groove as well. (Plates 9.10

and 9.11) Personnel at the Chhattrapati Shivaji Maharaj Vastu Sangrahalaya

143

also in Mumbai (also known as the Prince of Wales Museum) and the Regional

Museum of Natural History, Mysore, showed the researcher thermocol (Poly

urethane foam) sheets used for spreading insects, along with some properly

spread out and pinned insects on them. The Entomology Division of the Forest

Research Institute, Dehradun did mention that the insects are spread according

to the standards followed for the respective orders, but did not show the tools

and techniques used by them.

Used mainly for spreading the butterflies and moths, spreading boards are

often referred to as butterfly boards. Butterflies are pinned vertically through the

centre of the thorax. With the help of this pin the specimen in pushed straight

down in the centre of the groove of the setting board, until the wings on either

side are level with the two pieces of the board. If, the pin is slanted in any

direction in the groove, the dried specimen will be at a constant angle, so the

pin should be inserted straight. Once, the wings are comfortably placed on the

slats on either side, an insect pin should be inserted lightly near the front

margin of the fore wings just behind one of the heavy wing veins (as there is

less likely hood of tearing the wing). Then using a blunt end forceps or an

insect pin or needle, the forewing (as selected) is moved forward from near the

base of the wing, along the front margin until the hind margin is at right angles

to the length of the insect’s body. With a pin placed behind the heavy vein of

the hind wings, each hind wing should be moved forward until the gap between

the front wing and hind wing is almost just a notch. This side of the insect body

should then be covered with narrow strips of paper, because the wings often

tend to pull down to their original positions. The material of the paper for the

strips should be such that it is able to exert sufficient pressure on the wings,

keeping them in place. Stiff yet smooth pieces of waxed paper or index cards

suffice the requisition. Strips of transparent paper or plastic will allow seeing, if

the wings have slipped out of place. Either entomological pins or lace pins with

larger glass heads or glass headed map pins are used for the purpose.

The entire technique should be repeated for the pair of wings on the other side

of butterfly/ moth. Insect abdomen, antennae and appendages need proper

support at the time of spreading. Besides Lepidopterans, spreading insects of

any other order might require certain modifications or adaptations in the

144

spreading procedure. Certain insects are spread with the wings of only one

side (especially, the left) spread. The researcher could not secure any

information regarding the spreading techniques of specific insect groups, from

any of the museums visited.

Double mounting -

Insects that are too small cannot be pinned directly on standard pins, if they

have to be preserved dry, these have to be pinned as ‘double mounts’. Double

mounting refers to mounting such small insects like mosquitoes on a minuten

or a point or a card, which in turn has to be mounted on a standard insect pin.

(a) Double pinning with minuten pins: Minuten pins are special pins which

come in several lengths and thickness. According to Hangay & Dingley, “These

are made in three lengths: 10 mm, 15 mm and 20 mm. They range from about

0.14 mm to 0.30 mm in thickness” (1985, p.128.). In this kind of mounting the

insect mounted on the minuten is pinned/ mounted on a support or a stage.

These are strips which might be made up of different kinds of material fine cork,

balsa wood, fine foam or plastazote, fine textured plastic, silicone rubber or

polyporous or pith (used earlier). Whatever be the material used, the grain size

should be fine, so that the minutens can be inserted straight into the stage and

are gripped properly. The stage is prepared by inserting into the choiced

(material) strip, a normal entomological pin (may be, continental and size 3).

Preparing such a stage helps to easily move the insect specimen by

manipulating the regular pin. Moreover the stage also acts as a shock

absorber. The minutens used in this method are usually made up of stainless

steel, they are pointed at one end and headless on the other; and should be

handled with forceps to prevent getting pierced in the finger. This method also

known as staging was evident in the following museums and/ like institute

amongst many visited. Bengal Natural History Museum, Darjeeling –

Rectangular white thermocol blocks were evident in this museum, which have

been used as the stage; Entomology Division, Forest Research Institute,

Dehradun; and the Gass Forest Museum, Institute of Forest Genetics and Tree

Breeding, Coimbatore, were the other two (Plates 9.12 and 9.13). (b) Point- mounting: Another kind of double mounting involves gluing or

sticking the insect to the tip of a slender, triangular structure known as the

point, which in turn has a normal sized pin (sizes 2 or 3) passed through it at

145

the broader end. Points are made up of stiff, good quality paper cards; acetate

sheet cards are used as points by beetle collectors. The triangles cut out as

point might be up to 12 mm in length and 3 mm in width. 3 X 5 index cards

have also been proposed as an option by some. Whatever be the material and/

or the dimensions of the point, the tip of it should be folded so as to make a

shelf for the specimen to sit on it. Some entomologists propose to bend the tip

of the point down at a 90 degree angle using forceps or fingers to make a flat

surface against which the insect should be glued. The bent at an angle is

important so that when the insect is in an upright position, the bent tip of the

point fits against the side of the insect. Cellulose based cement, diluted with

ethyl acetate, as proposed by Hangay and Dingley (1985, p.132.). or hide glue

or clear finger nail polish might be used in point-mounting. Some entomologists

proposed the use of Elmers white glue only for sticking the insect specimen to

the point. Too much glue will cause the insect to sink into the adhesive, usually

a drop is sufficient for the purpose. The insect to be mounted should be

touched on its right side against the point. According to Collecting and Curating

Insects (n.d.), “In most cases, this should be against the thorax or anterior

portion of the abdomen.” (p.17). The orientation of the insect in this kind of

mounting will vary with the order of the insect specimen. For this and to keep

the insect straight and level in both directions on the point, it is important to

manipulate the specimen before the adhesive dries. This should be done using

a needle or a pair of fine entomological pins, preventing the specimen from

sinking deep into the adhesive, or smearing of the body parts (legs/ wings) with

the glue. A stronger mount shall be obtained if the top of the point can be

slipped between the body of the insect and adjacent leg. Only at the National

Forest Insect Reference Collection of the Forest Research Institute in

Dehradun, the researcher had come across point mounted specimens,

amongst the reserve collections of insects. Coleoptera Section of the

Zoological Survey of India, Kolkata has several such specimens, and stored

very well indeed.

(c) Card - mounting: An alternative method of double mounting of insects

using cards and glue is card-mounting. This method usually makes use of

rectangular cards, although oblong shaped ones with rounded corners are also

used. Hangay and Dingley proposes the use of good quality white card

preferably Bristol board for the purpose. If card rectangles are used,

146

dimensions of 5 x 8 mm or 5 x 12 mm might be used, depending upon the size

of the specimen (Prakash, 2001, p.13.). In card-mounting, the specimen is

mounted laterally at an angle of about 45 degree on the card chosen, using a

drop of gum (clear cellulose acetate cement/ white (casein) glue/ finger nail

polish/viscous poly vinyl acetate). Besides the water soluble media, many

entomologists even propose the use of alcohol soluble shellac gel as the

adhesive. Adhesive should be of the right consistency (i.e., neither too thick nor

too thin). Hangay and Dingley (1985, p.132.) proposed the use of fine setting

spatula or Leonhard (feather light) forceps or a fine setting (dissecting) needle,

to handle the insects. The legs, antennae, mouth parts, wings, etc., should be

spread using a fine, camel hair artist’s brush. If the insect has long legs or long

antennae, they should be folded slightly. Finally the well spread out insect is

placed on the glue on the card, with a wet artist’s brush. The glue in turn should

be applied using a setting needle or a piece of fine wire. Some entomological

specimens should be mounted on their backs, when ventral surfaces are

required for identification. At the time of mounting, no part of the insect should

hang from the card edges.

The Bombay Natural History Society, Mumbai; the Entomological Division of

the Forest Research Institute, Dehradun and the Gass Forest Museum,

Coimbatore are amongst those visited, where card-mounted insect specimens

are present. The Indian Museum, Kolkata, and the Government Museum,

Chennai, did approve the presence of carded entomological specimens in their

custody. Beside rectangular and triangular cards, circular discs are used for

mounting insect specimens at the Bombay Natural History Society, Mumbai;

Forest Research Institute, Dehradun and the Gass Forest Museum,

Coimbatore. (Plates 9.14 to 9.18)

Microscope slide mounting-

Some insects are so minute that they have to be mounted on slides and then

identified under a compound microscope. The following procedures should be

carried out to mount specimens in a way so as to make good slides.

(a) Maceration: Maceration eliminates the external secretions, foreign matter,

some organs, muscles and fat bodies without damaging the sclerotic or

chitinous parts, needed in slide preparation. For this, the insect specimen

147

should be immersed in a suitable agent like caustic potash solution/ caustic

soda solution/ lactic acid or lacto phenol. For delicate specimens and genitalia,

soaking the specimen or the insect body part to be mounted overnight in the

cold solution of the chosen agent is sufficient. For quicker penetration bigger

and whole specimens should be punctured or have a slight cut in the skin

under the base of the abdomen. Such specimens might be boiled as well for 1-

5 minutes as required, simply in a test tube on a Bunsen burner. Oldroyd,

(1958) suggests, “A safer method is to put the specimen in a small dish and

heat the dish on a tray of sand, made from a tin lid.” (p.138).

(b) Washing: For removing the agent used for maceration, the insects or body

parts may be rinsed under a tap, or poured into a clean dish of porcelain – from

this individuals are picked up using forceps and placed into clear water in

another container. Adding a drop of acetic acid (white vinegar) will guarantee

that no caustic remains.

(c) Dehydrating and cleaning: In case the specimen has become very dark

after maceration, it may be bleached, so as to reveal the required detail at the

time of study. A weak solution of bleaching powder to which a drop or two of

glacial acetic acid has been added; another chlorine bleach such as Parazone

or; a mixture of ammonia solution and hydrogen peroxide solution in the ratio of

1:6, are amongst options of suitable bleaching agents. In case the specimen

has become very transparent, staining is done. Aphids, lice and scale insects

might be stained in acid fuchsin, a solution in 20% alcohol is useful.

Microlepidoptera might be stained using chlorozol black. Whether bleached or

stained or only washed, the insect or its parts should next be dehydrated. If the

preparation consists of only chitinsed structures, the specimen should be

placed in glacial acetic acid for about five minutes to remove all of its water

contents. If the slide is to be made of soft tissues, the specimen should be

placed into grades of alcohol of gradually increasing strength starting from

30%, through 50%, 70%, 90% and finally absolute alcohol. Cellosolve is

another option. The length of time varies between 10 to 20 minutes depending

on the size of the specimen. Prakash (2001) said that: “During each transfer,

the specimen must be pressed with a seeker to ensure that the alcohol

penetrates all the parts of the insects.” (p.16). After dehydration, the specimen

must be cleared in clove oil/ cedar wood oil/ xylene, etc. The specimen must be

allowed to remain in the clearing fluid only for the time required for it to become

148

a little transparent. Both for dehydration and clearing solid watch glass should

be used, so that they do not tip over, and should be covered with a glass cover.

(d) Mounting: There are different kinds of mounting media, the standard being

Canada balsam. Another mountant Euparal is advantageous over others

because the little air bubbles formed during slide preparation, are absorbed by

the medium during drying. The specimen might not be dehydrated if Euparal is

to be used, which is a fast drying medium. Some other media include ‘Depex’,

or aqueous mounting media like Hoyer’s medium and PVA (polyvinyl alcohol).

The mounting medium chosen should of the right consistency, just liquid

enough to run, neither too thick nor too thin. Firstly, one or more drops of the

mountant should be poured on the specimen using a glass rod. The specimen

should be properly aligned in the mounting medium using a fine needle and

completely immersed. Also no air bubbles should be present. The cover slip

selected should be cleaned and ready at hand and placed on the readied

entomological specimen at a slight angle using a pair of forceps or using a pin

to support an edge. The cover slip, dropped flat with fingers, will trap the air

bubbles. In case of a thick specimen, chips of glass or plastic props should be

put around it to prevent the specimen from being crushed by the cover slip.

Special mounting rings also serve the purpose.

(e) Ringing: Any slide preparation intended to permanent should be ringed,

(using any suitable varnish or special compounds), so a circular cover slip

should be used. Ringed mounts have a hard protective rim, which prevents the

mountant from shrinking away from the edge and air is disallowed entry from

below the cover slip as well. According to Oldroyd (1958, p. 143), “To do this

needs a ringing - base, a rotating stand on which the slide can be spun while a

brush charged with ringing paint is held against the edge of the cover-slip.”

Canada balsam and Euparal mounts need not be necessarily ringed, as they

harden easily. Only the Entomology Division of the Forest Research Institute,

Dehradun has shown their slide collection to the researcher. The personnel

there did say that they follow the standard procedures to preserve their

entomological holdings; the procedure followed by the Division to prepare the

microscopic slides was not revealed. The Coleoptera Section of the Zoological

Survey of India in Kolkata also has a slide collection. One unique thing in the

slide preparation procedure of the Section is that the usual step of dehydration

149

is not followed. Instead the genitalia (now devoid of any fat content), is washed

with water a few times. (Plate 9.19)

Liquid preservation of insects-

Beside soft bodied, fragile adult insects, insect larvae and nymphal stages,

liquid preservatives are also suitable for keeping duplicates of the large number

of insects obtained using light traps. Bulk samples if kept unsorted 95% ethanol

is useful. Insects that have been collected alive are also best preserved in this

way. Insects belonging to the orders - Thysanura, Collembola, Ephemeroptera,

Isoptera, Plecoptera, Embioptera, Psocoptera, Pthiraptera, Thysanoptera and

Homopterans like the aphids and white flies, are usually considered soft

bodied, hence require liquid preservation. Orthoptera (crickets), Blattodea

(cockroaches) and Trichoptera (caddisflies) are also considered by some as

soft bodied. The most common of all being spirit, i.e., 70%-80% ethyl alcohol.

The concentration of ethanol (another name of ethyl alcohol, besides grain

alcohol), used to store entomological specimens varies with the type of insect.

But mostly it is recommended to add a few drops of glycerine to the alcohol.

This prevents stiffening and helps to relax the specimens. Any fluid

preservative is supposed to stabilize the specimen, prevent autolysis and be

germicidal. Ethanol suits most entomological specimens. Hence, it has been

used by most of the museums and/ institutions visited, where soft bodied

insects or the nymphs and larvae of insects of other orders have been

preserved. 9 of all the collections surveyed reported the presence of wet

preserved insect specimens. These include – Indian Museum, Kolkata; Bengal

Natural History Museum, Darjeeling; Regional Museum of Natural History,

Bhubaneswar; Government Museum, Chennai; Gass Forest Museum,

Coimbatore; Isoptera, Orthoptera and Coleoptera Sections, at the Zoological

Survey of India in Kolkata. This data has been represented in the Table 9.1,

also containing a chart corresponding to the data.

The researcher has taken into consideration both the insects on display as well

as those present in reserve. The maximum number was observed at the

Regional Museum of National History in Bhubaneswar. Here, probably only one

(a queen termite collected from a wooden panel/ structure of the Museum

building itself), wet preserved specimen is on display. The least number of

150

specimens were at the Gass Forest Museum in Coimbatore. Here, two wet

preserved specimens were on display. Although the former has approximately

60 wet preserved (70% alcohol) specimens in the reserve collection, the latter

is reported to have no reserve collection of insects in their custody. (Plates 9.20

to 9.25) All the specimens at the Isoptera Section at the headquarters of the

Zoological Survey of India in Kolkata are fluid preserved. The specimens at the

Isoptera section, Zoological Survey of India, Kolkata are preserved

permanently in 70% - 80% rectified spirit. (Plate 9.26) Prior to long term

preservation, some insects and most of the larval forms must be fixed. Fixing

helps to retain their colour, prevents blackening of specimens and at times,

delay the process of colour change, which is inevitable in case of direct

preservation for a long term. Either of these ways must be followed – killing the

live larvae by placing them in boiled (180ºF) water; using special chemical

solutions, like formalin, it is possible to kill and fix insect larvae; the Regional

Museum of Natural History, Bhubaneswar, uses 4% formalin solution as a

fixative. A special fixing solution is the kerosene-acetic acid-dioxane (KAAD)

solution (1:2:1 in 10 part alcohol). 30 minutes exposure is sufficient for smaller

insects but a medium sized one (caterpillar) might require (2-3) hours.

Saturated picric acid is suggested by some entomologists but it imparts its

yellow colour to the specimen.

Storing Insects: Storing Dry Preserved Insects –

Excluding the science centres, the museums and/ like institutions visited by the

researcher, all had dry preserved entomological holdings. The insects

preserved dry are usually stored in wooden boxes, after complete preparation

of the specimens. These boxes for permanent storage are invariably

rectangular and flat, so as to stack them easily in a pile. Rectangular boxes

with a glass top and all the remaining sides made up of wood, is the usual

choice. But boxes of similar shape and all the sides made up of wood might

also be used. The former is commonly seen because it performs the dual

function of a display box as well (when exhibits are change after some time).

Moreover, the glass top minimises the need of opening the lid of the box every

time, the insects in it are to be consulted. 9 museums and/ institutions part of

the present research work, were found to use wooden boxes provided with

151

glass tops, for storing their respective insect collections. These are – Indian

Museum, Kolkata; Regional Museum of Natural History in Bhubaneswar and in

Mysore; Bombay Natural History Society, Mumbai; National Museum of Natural

History, New Delhi; Entomology Division, Forest Research Institute, Dehradun;

Government Museum in Chennai; Orthoptera and Coleoptera Sections,

Zoological Survey of India in Kolkata. Bombay Natural History Society,

Mumbai; Regional Museum of Natural History in Mysore; Orthoptera and

Coleoptera Sections also use boxes with both sides of wood. Moreover, the

former two of these four museums, use both sides of such boxes for pinning

insects, in their collections. Full data has been presented through the Table and

a chart 9.2. Such boxes must be stored in an upright position on shelves, as is

evident at the Bombay Natural History Society, Mumbai. (Plates 9.27 and 9.28)

Of the remaining visited, the Patna Museum, Patna, and the Central Museum,

Nagpur, do not have any reserve collections, as is the case at Science City,

Kolkata, and at the Butterfly Park, Bannerghatta Biological Park in Bengaluru.

From the Orissa Agricultural University Museum at Bhubaneswar and the Gass

Forest Museum, Coimbatore, no information on insect storage could be

collected. The reserve collection of the Bengal Natural History Museum,

Darjeeling, had been sent to the ‘Interpretation Centres’ for identification.

Bombay Natural History Society, Mumbai uses a special kind of box which has

a glass bottom besides the glass top. Insects are pinned down the 3 thin strips

of wood, ply being affixed vertically along the glass bottom. (Plates 9.29 and

9.30) Most of the museums and/ like institutions have informed the use of the

standard size of the insect box, available commercially. But, it is a good option

to use storage boxes customized to suit the needs of the particular collection.

The Regional Museums of Natural History in Mysore and in Bhubaneswar, use

insect boxes customized to meet their requirements. (Plate 9.31) Most

museums and/ like institutions visited have stopped collecting insects, so have

insect storage boxes with the traditional cork lining, covered with white paper at

times. Only those who still collect (usually forced/ gifts/ donations/ projects/

identifications) have the modern plastic foam lined insect storage boxes, for

example, the Bombay Natural History Society in Mumbai. Personnel at the

Regional Museum of Natural History in Mysore have even used rubber sheets

as the lining of the insect box. (Plates 9.32 and 9.33) Beside boxes, glass top

insect drawers might also be used to store dry entomological specimens.

152

Commercially available Cornell drawers are similar in constitution. Drawer like

arrangement was seen at the Government Museum, Chennai; Entomology

Division Researcher Institute, Dehradun and Bombay Natural History Society,

Mumbai. While the first two museums had wooden knobs, at the Society, the

boxes had small metallic handles at the centre, for pulling out the drawers, at

the time of reference. (Plates 9.34 to 9.37) Unit trays are small enclosures with

their own lining of pinning material, proper dimensions of which should be used

to exactly befit the drawer or storage box. The use of unit trays inside storage

boxes and the drawers for dry insect collections, facilitates easy rearrangement

of the collection without having to handle (move) the specimens individually.

Hardly any of the Indian museums and/ like institutions being spoken of have

been found making use of unit trays. (Picture 9.2)

Live ants, cockroaches, dermestid and carpet beetles and book lice are the

insect intruders, beside rodents, lizards and others capable of damaging the

stored insect collection. Beside, using tight lids and storing in the darkness,

repellents and disinfectants have to be used for protecting the reserve

collections. The most commonly used being naphthalene balls (moth balls).

More than 50% of the museums and/ like institutions included in this research

work, use naphthalene to keep off all the potential pests. Two museums,

Regional Museum of Natural History, Bhubaneswar and Bengal Natural History

Museum, Darjeeling, use naphthalene balls. That napthalene affects foam

lining (causing it to melt or curl), should be taken care of. (Plate 9.38 - 9.40)

Table 9.3 tells about the other techniques of preservation used by the other

museums and/ institutions surveyed by the researcher.

Regulating the relative humidity (RH) in the exhibit space and collection storage

areas is an essential part of preventive conservation. So as to prevent moisture

accumulation causing growth of fungus and mould, hygroscopic substances

should be used. Silicon dioxide more common as silica gel is one such

material. Bengal Natural History Museum in Darjeeling uses silica gel inside the

boxes containing dry preserved insects. Bombay Natural History Society,

Mumbai also uses silica gel (to keep off moisture), but in an activated form (i.e.,

by heating to a temperature of 110ºC) wrapped in a muslin cloth and pinned at

one of the corners of the insect box. This treatment of the silica gel is termed as

153

conditioning to the desired RH level, before placing it in the storage unit. Most

of the other museums and/ like institutions believe in maintaining air tight

conditions and properly controlled temperature and relative humidity (RH) in the

storage area. The latter is possible through the use of devices to regularly

measure the temperature and RH, as evident at the Bombay Natural History

Society, Mumbai; Entomology Division Forest Research Institute, Dehradun

and the Butterfly Park of the Bannerghatta National Park in Bengaluru. The

personnel at the Forest Research Institute, Entomology Division, Dehradun;

Government Museum, Chennai believe in making the storage rooms air tight,

so the former has used a double door system beside keeping the doors and

windows closed, always, the same being practiced in Chennai as well. The

Regional Museum of Natural History, Mysore personnel use completely air tight

storage boxes to serve the purpose. (Plates 9.41 – 9.48) The following

museums and/ like institutions used cabinets to store their entomological

holdings – Regional Museums of Natural History in Bhubaneswar and Mysore;

National Museum of Natural History, New Delhi; Entomology Division, Forest

Research Institute, Dehradun; Bengal Natural History Museum; Darjeeling;

Indian Museum, Kolkata; Government Museum, Chennai; Bombay Natural

History Society and Chhattrapati Shivaji Maharaj Vastu Sangrahalaya, both in

Mumbai. (Plates 9.49 to 9.53; Picture 9.3) Some of these museums keep silica

gel in their cabinets to keep off moisture and prevent fungal attack; for example

Bombay Natural History Society, Mumbai. (Plate 9.54)

2) Storing Wet Preserved Insects and Related Material –

At the Bengal Natural History Museum, Darjeeling, a few wet preserved

specimens were present in the storage rooms. These were kept individually in

small jars provided with plastic lids, on top of the wooden cabinet. Most of the

insect collections had been sent for identification at that time to the

interpretation centres, so could not be studied. At the Government Museum,

Chennai, insects preserved in alcohol (of the appropriate grade/ percentage)

were present in the same storage rooms as that of the dry collections of

insects. At the Entomology Division of the Forest Research Institute in

Dehradun, the wet preserved insects collections were stored in wooden

almirahs having wooden framed glass panes (doors), standing along the wall

on the left side of the entrance to the room.

154

The usual choice for storing wet preserved entomological collections, are vials

or tubes. Depending on the size of the specimen(s) and their numbers it is

possible to use small, medium and large tubes. To prevent overcrowding or

specimens getting crushed, vials used should be of the width to accommodate

the specimens and of the height, to reach out at the bottom using forceps. Both

glass and plastic ones are available, but the former is the preferred option for

the long term storage. Again, shell vials are chosen over necked vials because

the former allow easy movement of specimens and their corresponding labels

in and out of the vial. Vacutainers – sterile glass or plastic tubes with closures

evacuated to create a vacuum inside the tube facilitating the draw of fluid, have

been recommended for small samples. At the Regional Museum of Natural

History, Bhubaneswar, thin small tubes are used to store collections of smaller

insect groups like Chalcids, Dipterans, bees, ants (red and black types), etc. A

little larger (medium) sized vials, are used to preserve insects like, the larval

forms of the Eri silk worm. The smaller vials used for preserving wet collections

are far more in number than the medium sized vials (a few only). At the

Isoptera Section, Zoological Survey of India, Kolkata, the individual insect

specimens or groups or part of the sample collected are stored in vials of

different kinds. Glass is the preferred choice as the vial material. Each such vial

is fitted with a cotton plug near the month, beside the regular respective

stopper. The containers used (provided) at present to the Section for individual

specimens or for bulk storage, are necked. Taking out specimen(s) from

necked vials & handling vials within necked jars/ bottle is very difficult, so

usually is not preferred. The usual choice is container(s) with straight sides,

rarely available and/ provided now. Racks at the Regional Museum of Natural

History, Bhubaneswar are made using rectangular thermocol blocks, in which

holes have been made to hold the thin, small vials used at the museum. The

tubes should be put around the outside of the jar, with their tubes visible, and

the middle is stuffed with cotton wool. This reduces the movement of the tubes

and allows easy reference at any given time. The method of storing vials

explained thus is evident, at the Regional Museum of Natural History,

Bhubaneswar. For example, ant collections in small thin vials were placed

inside a jar packed with cotton wool at the centre, only difference being the jar

was a plastic one, and not of glass. This is also the case at the Isoptera Section

155

of Zoological Survey of India in Kolkata. (Plates 9.55 and 9.56) Wide mouthed

glass jars are the usual choice for storing vials or for storing specimens directly.

At Regional Museum of Natural History, Bhubaneswar, many insects were

stored inside glass jars like several larval forms together, examples of beetles,

potter wasps; wasp adults & pupal stages; Queen termite, etc. The Isoptera

Section of Zoological Survey of India also uses glass jars for bulk storage.

Simple flat sheets of glass used as lids require a sealant, for example -

petroleum jelly or jar cement. Another successful option is screw cap with

polyethylene or made up of flexible polypropylene with Teflon liners.

Just like cabinets and shelving units are used to store insect boxes and

drawers, customized cabinets and shelves are also required to store wet

collections in vials and jars. Cabinets consisting of pull out drawers or provided

with movable partitions and dividers or elongated carriers might be used.

Similarly, shelving unit containing cabinets might serve the purpose. Any type

of storage equipment used, the containers should be arranged size wise from

top to the bottom. Any museum equipment for storing wet preserved insect

collections must exclude light, a cool and dark storage area is best. Specialised

shelving units made up of steel and proper locking mechanism, are quickly

replacing the traditional wooden cabinets and steel almirahs, at the Isoptera

Section of the Zoological Survey of India headquarters, in Kolkata. (Plate 9.57)

Wet collections run the risk of dehydration, due to evaporation of the liquid

preservative, specimens must be positioned into the storage container head

first, to avoid being damaged in case of any evaporation. So, the levels of

preservatives must be checked on a regular basis and topped up when

necessary. Fluid preservatives need replacement when their original colour

changes to the extent that the contaminant can stain the specimen(s),

damaging it in the process. If required the pH of the fluid should be checked

using a pH strip or a pH meter, too acidic liquid must be replaced.

Storing Slide Collections of Insects and Parts –

Larger slide collections might be stored in slides boxes. These have grooves

which hold slides in position and keep them apart from one another. “Slide

boxes should be uniform in size, generally 7” X 9” and have a 100 slide

156

capacity.” (Cochrane, 2006, p. 58.). The slide boxes shown to the researcher

by the personnel of the Entomology Division of the Forest Research Institute

(FRI) in Dehradun could also accommodate 100 slides each. (Plates 9.58 and

9.59) Slide boxes might be of two types – one is the poly propylene box with a

clasp lock and metal hinges, the other is made up of paper board and provided

with plastic hinges. Slide boxes might be stored in either of the two ways, (a)

On open shelves in an upright position, so that the slides lay horizontally, with

the sides containing the mounted specimens, facing upwards. (b) Another way

is to use cabinets, which consist of trays to hold the slides horizontally. The

Entomology Division, Forest Research Institute, Dehradun follows the latter

kind of arrangement as well to store their rich collection of slide-mounts. (Plate

9.60)

Accessories to Store Insect Collection More Safely: (a) Cabinet Platforms or Casters - Raising the cabinets and shelving units on

platforms or casters, keep the storage equipment off the floor by a few inches.

(Picture 9.4; Plates 9.61 and 9.62)

(b) Stacking Rims - Metal stacking rims provide collars to secure the top

cabinet, thus preventing it from sliding off the bottom cabinet.

Although in some of the museums and/ like institutions visited cabinet platforms

were evident for the safety and security of their cabinets and shelving units

used to store their rich, varied insect collections, but particular presence or

absence of stacking rims remained unexplored. Most of the storage units laid in

direct contact with the floor, except those which stood on their legs remained

raised above the floor by a few inches. An example is the regular steel almirah

used at the Bombay Natural History Society, Mumbai.

Labelling the Insect Specimens: For specimens directly pinned – the locality label in case of specimens smaller

than the surface area of the label, pinning should not be through the centre of

the label, this keeps the label almost centred under the body of the insect

specimens with the long axis of the label coinciding with the long axis of the

specimen. But for the specimens larger than the surface area of the label, the

pin should pass through the centre of the label, aligning the label transversely,

157

at right angles to the axis of the body of the insect. In case of insects mounted

by direct pinning, the text lines of the label must run parallel to the long axis of

the specimen and read from left to right. For double-mounted insects, the pin

should be inserted through the centre of the right side of the label, such that the

label long axis is aligned in the same direction as the card point. In case of

pointed specimens, the text lines of the label must run parallel to the long axis

of the point. Be the insects mounted by direct pinning or pinned through double

mounting, the locality label should not obscure the view of the central surface of

the specimen but be at the height to allow another label to be placed below,

with sufficient room between the two to enable easy reading of the lower labels,

without having to move any of the labels.

In the museums studied, all the labels were legible at the Bombay Natural

History Society in Mumbai, Gass Forest Museum in Coimbatore, National

Forest Insect Reference Collection in Dehradun, Orthoptera & Coleoptera

Sections of the Zoological Survey of India (Kolkata).

Even for the insect specimens requiring liquid preservation consideration of

both paper and ink are important. High quality, low fibred cotton rag paper i.e.

100% cotton stock (neutral to mildly acidic) is the most preferred. Paper weight

is also important, light papers run the risk of getting torn easily and cardboards

(or paper of such consistency) are too stiff to fit at ease against the inside curve

of the storage vial. The label inks must be tested for fading, bleeding and the

durability of surface. Carbon-based, black inks which do not dissolve in water/

alcohol/ formalin solutions, must be used. Using a water proofing spray (artist’s

fixative) on the labels, after they have dried, also helps. A quick dip of the label

in dilute acetic acid (vinegar) will also fix the ink on the label paper. If ethanol is

the fluid preservative used, ethanol proof ink, for example – Micron archival ink

pens are available for use. The fluid preserved specimens at the Regional

Museum of Natural History in Bhubaneswar usually use pencils for writing the

labels. For placement the label should be rolled up and slipped into the

corresponding vial. Labels should never be placed on the outside of the jar, to

avoid damage/ destruction by pests or otherwise; to prevent detachment and

for easy transfer along with the respective vial contents (in case of change of

vial). The specimens should neither be harmed by the labels, nor should they

158

obstruct the legibility of the label. Usually there will be more than one label per

specimen or group; these must not lie face to face. The label text should

always face the exterior; with the left margin of the label at the bottom of the

vial, to enable correct direction of reading the label(s). Locality, identification

and required labels were seen inside the vials containing the fluids preserving

specimens, both at the Regional Museum of Natural History in Bhubaneswar

and at the Isoptera Section of Zoological Survey of India in Kolkata. The labels

in both the places did not have the names of the fixative and/ preservative

used. The former had data under the following heads – Name of the specimen,

Date of collection, Name of the collector(s), Locality (inclusive of the city of

collection). (Plates 9.63)

The slides shown at the Entomology Division of Forest Research Institute in

Dehradun had adhesive-backed square labels stuck vertically, on the right

hand side of the slides. The data heads in the labels were – Scientific name of

the specimen, determined by, registration and/ accession number. In case of

type specimens or their body parts mounted on slides, similar square shaped

labels are stuck on the left hand side of the slides, horizontally. The label data

included – the accession number, name of the insect order, scientific name,

locality, date of collection and name of the collector. (Plates 9.64 and 9.65) Although not slides (of glass), some of the insect specimens and their life

stages have been mounted on slabs of glass/ glass tablets and labelled in

different ways, at the National Museum of Natural History in New Delhi. The

researcher had observed that the almirahs/ shelves/ cabinets/ other furniture

used for the purpose of storage in the museums and/ institutions, were

provided with numbers, in most of the cases, but at the Bombay Natural History

Society, something unique was observed. Here even the keys to the cabinets

had proper labels. (Plates 9.66 and 9.67) The Society and the National Forest

Insect Reference Collection (Entomology Division, Forest Research Institute,

Dehradun), both have the names of the genus, of the insect specimens present

in the particular storage drawer, printed and pasted (in case of the former) and

inserted in the holder (in case of the latter), on the outside. The later method is

also the way followed in the Sections of the Zoological Survey of India

(Coleoptera and Orthoptera), visited by the researcher. (Plate 9.68)

159

References

Chan, K. (2010). Basic ways to preserve insect specimens for display.

Retrieved May 25, 2015 from https://suite.io/ken-chan/3wzy2kj

Browne, F. B. (1927). Insects. London: Williams & Norgate

Ltd.

Cochrane, M. (2006). Natural history collections division: Terrestrial

invertebrate collection. Collection management manual. Capetown:

South African Museum.

Collecting and curating insects. (n.d.).

Hangay, G., & Dingley, M. (1985). Biological museum methods. Volume 2:

Plants, invertebrates and techniques. Sydney: Academic Press

(Harcourt Brace Jovanovich Publishers).

Insect collection guide. (2013).

Knausenberger, W.E. (1986). Island Insects – Handbook for insect study.

Lysyk, T. J. (revised 1995). The Insect Collector’s Guide. Entomological

Society of Alberta.

Millar, I. M., Uys, V. M. & Urban, P. R. (2000). Collecting and preserving insects

and arachnids. SAFRINET.

National Park Services. (1999). NPS Museum Handbook, Part I. Washington,

D. C. Retrieved March 18, 2009 from

www.nps.gov/museum/publications/MN1/mushbk1.html

Neel, C. S. (revised 2000). 4 – H Entomology: Unit II. University of Kentucky

Department of Entomology.

Oboyski, P. T. (2007). Techniques in entomology. Retrieved October 12, 2013,

from http://nature.berkeley.edu/~/poboyski67/download/Techniques.doc

Oldroyd, H. (1958). Collecting, Preserving and Studying Insects. Hutchinson &

Co. (Publishers) Ltd.

Prakash, A. (2001). Laboratory manual of entomology. Noida, India: New Age

International (P) limited.

Schauff, M. E. 1986 (revised 2005). Collecting and Preserving Insects and

Mites: Tools and Techniques. United States Department of Agriculture.

Retrieved September 06, 2013, from

http://www.ars.usda.gov/main/site -main.htm?docid=10141&page=1

Plate 9.1 (left): Carbolic acid used by the personn el at the Bengal

Natural History Museum, Darjeeling

Plate 9.2 (right): Glass dessicators at the ‘Insect ary ’of the Forest

Research Institute, Dehradun

Plate 9.3: The apparatus used for relaxing the inse cts (killed), at

the Orthoptera Section, of the Zoological Survey of

India in Kolkata (above)

Picture 9.1: A pinning block (below)

Plate 9.4 (left): Entomological pins used by the Bo mbay Natural

History Society, Mumbai

Plate 9.5 (right): Entomological pins used at the O rthoptera Section,

Zoological Survey of India, Kolkata

Plate 9.6: Pins and stretching board used at the Go vernment Museum,

Chennai

Plate 9.7 (left): Stretching board used at the Orth optera section,

Zoological Survey of India, Kolkata

Plate 9.8 (right): Adjustable screw at one end of t he same stretching

board

Plate 9.9: Stretching and pining in progress at the Regional Museum of

Natural History, Bhubaneswar

Plate 9.10 (left): Stretching board of the Bombay N atural History

Society in Mumbai

Plate 9.11 (right): Adjustable screw at one end of the same stretching

board

Plate 9.12 (left): Rectangular thermocol blocks use d at the Bengal

Natural History Museum, Darjeeling

Plate 9.13 (right): Double mounting at the Gass For est Museum,

Coimbatore

Plate 9.14 (left): Card mounted specimens at the Ga ss Forest Museum,

Coimbatore

Plate 9.15 (right): Circular cards are used at the Gass Forest Museum for

mounting insect specimens

Plate 9.16 (left): Triangular cards used at the Gas s Forest Museum,

Coimbatore

Plate 9.17 (right): Differently shaped cards used f or mounting at the

Bombay Natural History Society, Mumbai

Plate 9.18: This insect box from the National Fores t Insect Reference

Collection of the Forest Research Institute in Dehr adun,

shows all types of double mounting of entomological

specimens – on minutens, points and cards

Plate 9.19: Slide preparation in progress at the Co leoptera Section,

Zoological Survey of India in Kolkata

Plate 9.20 (left): Liquid preserved specimens on di splay at the Gass

Forest Museum, Coimbatore

Plate 9.21 (right): Formalin solution is used at th e Museum as the

preservative, its preparation was on display

Plate 9.22 (left): Liquid preserved stages of silk worm displayed in the

Insect Gallery, Indian Museum (Kolkata)

Plate 9.23 (right): Liquid preserved specimens as e xhibits at the

Government Museum, Chennai

Plate 9.24 (left): Locust preserved in fluid at the Bengal Natural History

Museum in Darjeeling

Plate 9.25 (right): Liquid preservative is the only material required for

preservation of specimens of the order Isoptera, at the

Zoological Survey of India, Kolkata

Plate 9.26: 70% - 80% rectified spirit used at the Isoptera Section

Plate 9.27 (left): Lepidoptera specimens pinned on both the sides of

the insect box, at the Bombay Natural History Socie ty,

Mumbai

Plate 9.28 (right): The boxes kept in an upright po sition in the shelves of

the steel cabinets at the Society

Plate 9.29 & 9.30: Butterflies pinned along the ply strips of a specialized

storage box at the Bombay Natural History Society.

Dorsal side is seen on the left. Ventral side is se en on

the right

Plate 9.31 (above): Latest kind of insect box used at the Regional Museum

of Natural History, Mysore

Plate 9.32 (below): Insect storage box with styrofo am lining at the

Bombay Natural History Society in Mumbai

Plate 9.33: An insect box with a different kind of lining in use at the

Regional Museum of Natural History (Mysore)

Plate 9.34 (left): Drawer like arrangement of inse ct storage boxes in the

reserve collection of the Government museum,

Chennai, each provided with two wooden knobs

Plate 9.35 (right): Single wooden knobs at the cent re of the insect

storage boxes used at the National Forest Insect

Reference Collection (NFIRC), in Dehradun

Plate 9.36 (left): Most of the insect boxes, at the Bombay Natural

History Society in Mumbai, have metallic handles at

the centre (to pull them out when required)

Plate 9.37 (right): Drawer like arrangement of the insect storage box at

the Society

Picture 9.2: Unit tray

Plate 9.38 (top): Napthalene balls used inside a s torage box at

the Bengal Natural History Museum in Darjeeling

Plate 9.39 (bottom): Insect box with crushed naphth alene (balls)

packed inside a paper envelope and pinned on

to the insect box, at the Bombay Natural History

Society

Plate 9.40: Napthalene balls crushed to powder f or use in

the insect storage boxes, at the Coleoptera

Section, of Zoological Survey of India in Kolkata

Plate 9.41 (top left): Silica gel used at the Benga l Natural History

Museum in Darjeeling in the insect storage units

Plates 9.42 & 9.43: Silica gel wrapped in mu slin (top right) and

pinned inside the insect storage box (bottom

left) at the Bombay Natural History Society,

Mumbai (bottom)

Plates 9.44: Temperature (left) and RH (centre) me asuring

devices at the Bombay Natural History Society

Plate 9.45 (right): Dry and wet bulb thermometer us ed at the

Butterfly Park in the Bannerghatta National Park of

Bengaluru

Plates 9.46: Temperature (left) and RH (right) meas uring

devices at the National Forest Insect Reference

Collection of the Forest Research Institute in

Dehradun

Plate 9.47 (left): Double door locking syste m at the Forest Research

Institute

Plate 9.48 (right): Maintaining airtight condition s in the storage area

(National Forest Insect Reference Collection), at

the Forest Research Institute

Plate 9.49: Steel drawers (unlabelled), storing dry preserved insects at

the Chhattrapati Shivaji Maharaj Vastu Sangrahalaya in

Mumbai

Plates 9.50: Steel almirah types, seen at the Bomba y Natural History

Society in Mumbai

Plates 9.51: Wooden cabinets of varied styles, also seen at the Bombay

Natural History Society in Mumbai

Plate 9.52 (left): This is the modern storage unit used by the Zoological

Survey of India, Kolkata. This has been photographe d

at the Coleoptera Section

Plate 9.53 (right): This is how the cabinet looks w hen unlocked. This has

been photographed at the Orthoptera Section of the

Zoological Survey of India, Kolkata

Plate 9.54: Silica gel wrapped in muslin, used insi de almirah

storing insect boxes, at the Bombay Natural History

Society (Mumbai)

Picture 9.3: Specialised entomology ca binet used by the National

Park Service Museu m

Plate 9.55 (left): Vials of different sizes, u sed at the Isoptera Section,

Zoological Survey of India, Kolkata

Plate 9.56 (right): Storage jars packed with vials , at the Section

Plate 9.57: Modern steel shelves, now being used at the Section

Plate 9.58 (left): An ideal slide box (empty) with a 100 slides capacity,

used at the Entomology Division of the Forest

Research Institute in Dehradun

Plate 9.59 (right): Another such slide box filled t o its complete capacity,

at the Entomology Division

Plate 9.60: Different types of slide storage u nits in use at the

Entomology division (Dehradun)

Picture 9.4: Cabinet platform

Plate 9.61 (left): Platforms at the base of one kin d of the wooden

cabinets used for storage at the Bombay Natural

History Society (Mumbai)

Plate 9.62 (right): Cabinet platforms in use, at th e Orthoptera Section, of

the Zoological Survey of India in Kolkata

Plate 9.63: Labels placed inside the jars at the Is optera Section

(Zoological Survey of India, Kolkata)

Plate 9.64: The square labels used on the slides of the Entomology

Division (Forest Research Institute) in Dehradun

Plate 9.65: Type specimen slides with square labels at the Entomology

Division (Dehradun)

Plate 9.66 (left): Labelled keys (for cabinets), se en at the Bombay

Natural History Society in Mumbai

Plate 9.67 (right): Most wooden cabinets, at the B ombay Natural History

Society, are provided with a number (on the left),

Family name (at the centre), and a detailed label ( on

the right) containing – the name of the genus, alon g

with the corresponding number of the specimens

present, in that particular cabinet

Plate 9.68: Names of the insect genus stored in the respective

drawers printed in black and inserted into the card

holders at the National Forest Insect Reference

Collection (NFIRC, Dehradun)

Table and chart 9.1

Serial No.

Museum / Institution LocationType of Storage Boxes Used for Dry Preserved Insects

1 Indian Museum Kolkata Wooden box with glass top

2 Science City Kolkata No such preservation

3 Bengal Natural History Museum Darjeeling Not shown

4 Regional Museum of Natural History Bhubaneswar Wooden box with glass top

5 Orissa University of Agriculture and Technology Bhubaneswar Not shown

6 Patna Museum Patna Absent

7 National Museum of Natural History New Delhi Wooden box with glass top

8 Entomology Division, Forest Research Institute Dehradun Wooden box with glass top

9 Chhattrapati Shivaji Maharaj Vastu Sangrahalaya Mumbai Steel drawers

10 Bombay Natural History Society � Mumbai Wooden box with glass top

11 Central Museum Nagpur Not shown

12 Government Museum Chennai Wooden box with glass top

13 Gass Forest Museum, Institute of Forest Genetics and Tree Breeding Coimbatore No information collected

14 Butterfly Park, Bannerghatta Biological Park Bengaluru Not shown

15 Regional Museum of Natural History � Mysore Wooden box with glass top

16 Nehru Zoological Park Hyderabad No information collected

17 Isoptera Section, Zoological Survey of India � Kolkata No such preservation

18 Orthoptera Section, Zoological Survey of India � Kolkata Wooden box with glass top

19 Coleoptera Section, Zoological Survey of India � Kolkata Wooden box with glass top

� In all these museums and/ like institutions an additional type of storage

box was found, both sides of which are wooden. Only at the Bombay

Natural History Society and the Regional Museum of Natural History in

Mysore, both the sides of such boxes were reportedly used for storing

the insects.

� Wooden box with glass top was found in this Section, but used only for

storing the sections of the termite nests' collected, hence not included

in the table.

5%11%

21%

5%47%

11%

Type of Storage Boxes Used for Dry

Preserved Insects

Absent

No such preservation

Not shown

Steel drawers

Wooden box with glass

top

Table and chart 9.2

Table 9.3

Other preservation chemicals and / techniques used by the museums with

insect reserve collections

Serial No.

Name of the Museum and / or Institute

Preservative and / Preservation technique Used

1 Chhattrapati Shivaji

Maharaj Vastu

Sangrahalaya

Cleaning of the collections and associated

furniture. The collections are sprayed with

Baygon and the wooden stuff with Tricel.

2 Bombay Natural

History Society

Creosote dipped in cotton is mounted on

a pin, in each of the insect boxes, in

addition to naphthalene (powdered and

filled in paper envelopes, for individual

boxes).

3 Bengal Natural History

Museum

Cotton dipped in a solution of camphor

and carbolic acid is present in the

showcases and the insect boxes, in

addition to naphthalene balls.

4 Entomology Division,

FRI

Fumigation of the collections using a

solution of creosote, crushed naphthalene

and carbon disulphide.

5 Indian Museum Cotton dipped in a solution of camphor

and carbolic acid is present in the

showcases and the insect boxes, in

addition to crushed naphthalene balls.

6 Government Museum Cotton dipped in a strong solution which

is a mixture of lysol and camphor, or a

mixture of chloroform, creosote and

naphthalene is mounted on pins inside

the storage boxes. Powdered

naphthalene or para – dichlorobenzene

crystals are also placed in the storage

units. Dilute solution of xylene with spirit

are also coated along the sides of insect

boxes, sometimes.

7 Regional Museum of

Natural History,

Bhubaneshwar

Phenol is used in addition to naphthalene

balls.

8 Regional Museum of

Natural History,

Mysore

Earlier napthalene balls or

dichlorobenzene were used, such

chemicals are no longer used. Actually

the boxes being used now, are completely

air – tight, maintaining the dryness as

required on the inside of the boxes.

9 Gass Forest Museum Napthalene in the powdered form is only

used.