Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. COLLECTION and PRESERVATION of INSECTS Miscellaneous Publication No. 601 _ U. S$. DEPARTMENT OF AGRICULTURE A Se Mt LE ee OS ST TES Fees NSECTS are of many kinds and differ greatly in their life histories and habits. From the viewpoint of man, some insects are injurious, some are unimportant, and some are beneficial. Because of these differences it is important to recognize insects, in order that our war against injurious species may be carried on effectively. Well-preserved and properly labeled specimens are essential to the identification of insects. This publication gives information on collect- ing, preserving, handling, mounting, and labeling insect specimens, on subsequent care of collections, and on recognition of the general insect groups, or orders. It has been prepared in response to numerous requests from farmers, students, servicemen, and other individuals and groups interested in obtaining first-hand knowledge of insects by col- lecting them. For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25,D.C. - Price 15 cents Washington, D. C. Issued 1946 COLLECTION AND PRESERVATION OF INSECTS By P. W. OMAN, senior entomologist, and ARTHUR D. CUSHMAN, chief scientific illustrator, Division of Insect Identification, Bureau of Entomology and Plant Quarantine, Agricultural Research Administration _Contents Page Pace HUTTE (iO, COIN oe A eS re 2i\s Protection from). pests— =. 24 Bqumment and collecting methods Packing and shipping specimens____ 25 Nets __——_____----------_----- Zi eeelivcuinsects: eammmmenrsen 0 25 Killing bottles ______________--- a Deaduinsectsm aa mee tena tiers S 25 Aspirator, or suction bottle______ Gi Packing for shipment vii La 5 Beating cloth, or umbrella_______ Ro hae op ES a eae “¥ Snr ack 7p tej gee ide eee g | Recognition of material ______ 25 Separators Pweg ee te ce eee 9 Thysanura 2 REE Te ee Si ee ms ae 28 @ollectine at lights 27-2 g| Collembola —_—_—_____ 28 Baits and bait trapses. =. eo 10 ee eae et 28 Tweezers, forceps, and brushes___ 10 SOD CET ake Sere teers te ee 29 é Plecoptera OC Rearing So. | SUS SS 29 ‘ = Smapsee Pose ts Ephemeroptera teed oe ed A S1 How to kill and preserve specimens 12 Odonat apes sae ae a nce Care and handling of unmounted PSOCOpberas sew mee eee Ue i 29 ICCC ee eee Pash Mallophngal ess see gee cae 0 ee 32 How to mount insects_____________ 14 Fee ae eae 32 Direch pimnIi se eee Tee TS IB ere: me ares era —________________ 33 MODE MOUNTS seen eee ee 18| «¢ meee pare —-----~-- a 33 imfationtotlarvacy sams.) 19 ee £08 ae ~--------~~--------- 39 Rikeremounte erase eae. | 20 Pie os era —_________________- 37 Spreading boards and blocks____ 20 oraptera ________________-_—~ 31 [BLY Fe ween 2 To a ne a 2° Ws GTO) ORE ee a oe 37 Labeling the specimens____________ 99| Mecoptera ~______------------- 38 What information is essential_____ 22 Trichoptera Se ee ee 38 How to make labels ________ yo) soe DIUODtelar we esr ee 39 Howelanelsschouldsbe pinned. 24 | Diptera —__-__________________ 40 Care of the collection ________-__-___ OAs Siphonaptera, = 22> ee 41 [SIGN a es ae OA laertymenoptera. = == = ieee es 42 EA Sasa ina ¥ aa Se ee Ee - WE ARE constantly at war with insects. Year after year insects are responsible for enormous losses in terms of disease and destruc- tion of food, clothing, and other materials of value to man. In order to combat insects successfully we must know them well; we must know where they live, what they feed upon, and how they develop. The habits of one kind of insect may be very different from those of another very similar in appearance. For this reason we cannot gen- eralize, but must obtain definite information about each species. The better we know our insect enemies, the better are our chances of antici- pating attacks and of preparing and conducting our defenses against them. We have to be ever on the alert for new pests and new outbreaks of old pests, and to do this we must be able to distinguish between insects that are injurious or potentially injurious and those that are beneficial or of no consequence to human welfare. Increasing knowledge of the damage done by insects, and especially recent discoveries concerning the role they play in the transmission of animal and plant diseases, emphasize anew the necessity for correctly identifying these pests. Otherwise we dissipate our efforts and misuse our ammunition, so to speak, in the destruction of beneficial or unimportant insects. Because the correct identification of insects is seldom easy, it 1s im- portant that specimens be preserved in as good condition as possible. The identification of a particular species of insect usually requires examination of minute details of its anatomy with the aid of a lens or a microscope. If these details are concealed or missing because of improper handling and preservation, then it is impossible to identify the specimens, and previously existing information about the habits, economic importance, and control of the SpE cannot be found and utilized. This bulletin has been prepared to fill the needs of farmers and other persons and groups interested in the study and control of insects. It is also intended for use in meeting the numerous requests received from those who desire information on methods of collecting and pre- serving insects. Furthermore, it should be helpful to agencies engaged in conducting insect surveys as a basis for pest control. Tt will give needed guidance in the collection of different kinds of insects and in the preservation of such material in a manner that will permit definite identification. The instructions given are necessarily brief. Additional information may be obtained by writing to the Bureau of Entomology and Plant Quarantine, United States Depart- ment of Agriculture, Washington 25, D. C. 2 MISC. PUB. 601, U. S. DEPT. OF AGRICULTURE WHAT TO COLLECT What to collect will depend on the purpose for which the material is intended. Insects which are important as pests and for which identification is needed should always be collected in numbers. A sam- ple of 20 specimens should be the minimum, and even more are desir- able. It is a good rule always to collect an adequate sample of all the different stages, regardless of whether the insect is observed to be a pest. Specimens can always be discarded or exchanged, but it is not always possible to collect additional specimens at the time they may be needed for study. Most persons will find it desirable to concentrate on one or two of the major insect groups. There are so many insects—more than 80,000 kinds are known in North America alone—that it is scarcely possible for one person to assemble a collection that includes examples of all those occurring in a single locality. The collection of specimens alone is not enough. Information about them is equally important. The collector should take advantage of opportunities to observe and record interesting facts about the habits and life histories of the different insects found, for in this way he may add important details to the growing store of knowledge that enables us successfully to compete with our insect enemies. EQUIPMENT AND COLLECTING METHODS The equipment required for assembling a representative insect col- lection need not be elaborate or expensive. Most needs of the average collector will be met by the items discussed in the following pages. Much equipment for collecting insects may be purchased from com- mercial supply companies, most of which will send catalogs and price lists on request. Below are given the names and addresses of a few such companies. The United States Department of Agriculture does not guarantee or endorse the firms listed or the reliability of their products. In furnishing this list no claim is made that it 1s complete. Carpocapsa (Geo. Franck, Manager), 375 Lehigh Avenue, Pittsburgh, Pa. Central Scientific Company, 1700 Irving Park Boulevard, Chicago, IIl. Clay-Adams Company, Inc., 44 East Twenty-third Street, New York, N. Y. Denoyer-Geppert Company, 5335-57 Ravenswood Avenue, Chicago, Ill. E. H. Sargent and Company, 155-165 East Superior Street, Chicago, Il. General Biological Supply House, 761-763 East 68th Place, Chicago, Il. Southern Biological Supply Co., Natural History Building, New Orleans, La. Standard Scientific Supply Corp., 34-38 West Fourth Street, New York, N. Y. Supply Department, Marine Biological Laboratory, Woods Hole, Mass. Ward’s Natural Science Establishment, 302 Goodman Street, North, Rochester, IN-aYs NETS Construction Although a considerable variety of nets may be purchased from supply houses, many collectors prefer to make their own. The insect net consists essentially of a cloth bag hung from a metal loop attached toa handle. Figure 1, which shows parts of a beating, or sweeping, net, illustrates the general principles involved in the construction of COLLECTION AND PRESERVATION OF INSECTS oo | ll 10'—+ pee aorasg | | _— 1g"— —-++— 8"— —_ - — 36"—- ————— — Figure 1.—The construction of a beating net: A, Steel wire loop 15 inches in diameter ; B, end of net handle showing grooves and holes into which the arms of the wire loop fit; C, net handle with metal ferrule to hold net in place; D, how to cut a single piece of cloth to make a round-bottom bag; EH, details of top part of net fitted over a section of the wire loop. the insect net, but the size and shape of the net and the material used will depend upon the purpose for which it is intended. The beating net must be strong enough to stand rough use. A handle of straight-grain hickory or ash, such as a hoe handle, is recommended. This should be fitted at one end with a metal ferrule (fig. 1, C) about an inch in diameter to hold the wire loop in place. The grooves in the handle should be made exactly as long as the straight arms of the net loop, so that the tips of the arms, bent at right angles, will fit into the holes bored in the handle at the end of the grooves. The rest of the handle should be about 13¢ inches in diameter and 31% to 41% feet long. The wire loop (fig. 1, 4) should be of steel wire which will spring back in shape if bent. For the beating net No. 12 steel wire (0.189 inch in diameter) is satisfactory, although even heavier wire is some- times preferred. After the loop is shaped it is usually desirable to have it tempered and, if this can be done at a factory or shop where steel springs are made, a most satisfactory net loop will result. For the bag for the beating net, 6-ounce drill, heavy muslin, or hght canvas is recommended. Figure 1, D, illustrates how a bag to fit a loop 15 inches in diameter may be made from a single piece of material. The four lobes, cut as segments of a circle, form the rounded bottom of the bag when sewed together. The slit at the top, which should be cut and hemmed as indicated before the top of the bag is folded over, permits the completed bag to be slipped onto the wire loop. The top margin of the material should then be folded down to the bottom dotted line and sewed in place; then this double thick- saa oe are ao = A MISC. PUB. 601, U. 8. DEPT. OF AGRICULTURE ness of material should be stitched through in a zigzag fashion and turned down again to form the wide hem by means of which the bag is attached to the wire loop. The details of this double-thickness hem as it hangs on the wire loop are shown in figure 1, #. Because that part of the bag gets the most wear it is usually advisable to make it of the double thickness of material indicated. The zigzag stitching keeps the outer thickness from fraying so badly when it wears through. If desired, a single thickness in the top band of the bag may be later reinforced by some heavy material, or, in the case of a hght-weight bag, the entire top band may be made of a stout material and the light-weight bag sewed to this. The final step is to complete the bag by sewing together the two ends of the material and the margins of the cut lobes. The completed bag may be slipped onto the wire loop by squeezing the loop together and sliding the net band on a little at a time. The beating net described above is not satisfactory for the capture of moths, butterflies, flies, wasps, and other swift-flying or fragile insects. For collecting these the nets described in the next three para- graphs will be found useful. x The general-purpose net should have a loop 12 inches in diameter and a bag of unbleached muslin or coarse- or medium-mesh brussels. This net should be tapered more toward the bottom than the beating net but should not come to a point. The handle need not be as stout as that for the beating net. 7 The butterfly net is hke the general-purpose net, but the bag is of good-quality marquisette or fine netting and the handle is a little longer and of hghter weight. This net is also useful in capturing dragonflies and other large-winged insects. The fly net should have a loop 8 inches in diameter and a bag of medium-mesh brussels or fine netting. The handle should be short and light.. The wire loop need not be so heavy as that for the beating net. ‘This net is also good for collecting bees and wasps. The aquatic net, for collecting insects that live in or on water or on aquatic plants, should not have a circular loop but should be either square, with the handle attached to one corner, or about semicircular, with the side opposite the handle straight. The bag should be shallow (about as deep as the length of the straight side in the semicircular net) and should be made of heavy scrim with a canvas band for the wire loop. The bag for any of the nets described above may be made of silk bolting cloth, which is very durable and comes with meshes of various sizes. However, bolting cloth is expensive and difficult to obtain and is not recommended for the general collector. The bag for any net, excepting the water net, should be long enough so that the tip may be flipped over the rim of the wire loop to form a pocket from which the netted insects will not escape. Care and Use Nets should be kept dry. A wet net damages the specimens and dampness causes the fabric to rot quickly. Aquatic nets should be thoroughly dried after use. COLLECTION AND PRESERVATION OF INSECTS 5 Although the beating net may be used on thorny bushes and trees, most other nets tear easily and should be used with care. Insects should be removed from the beating net after a few sweeps so that they will not be battered by the debris that accumulates in the net. Lively insects, such as leafhoppers, can be easily removed from the beating net with an aspirator. (See p. 7.) To do this, stand so that the open end of the net is not directly toward the sun, rest the loop of the net on your head, and, if possible, let the bag of the net be distended by the wind. Thus one hand is free to manipulate the bag and the other to handle the aspirator, while the head and arm of the collector fill the opening of the net sufficiently to prevent the escape of most specimens. In using the fly net or butterfly net, after the captured specimen has been enclosed in the tip of the net by grasping the bag with one hand a little from the end, insert the open killing bottle into the net and permit the specimen to drop into it. While the bottle is still in the net, cover the opening until the specimen becomes stupefied ; otherwise it may escape before the bottle can be removed from the net and closed. KILLING BOTTLES Construction Any fairly heavy glass jar or vial with a wide mouth is satisfactory for a killing bottle, and every collector should have several bottles of various sizes. Empty pickle jars, olive jars, and the like will fur- nish a considerable assortment of larger bottles, and smaller ones may be made from test tubes or shell vials 1 to 114 inches in diameter. These should be supplied with tight-fitting corks or screw caps. A and B of figure 2 illustrate two bottles of convenient shape. Figure 2, @, illustrates a convenient adaptation of a screw cap for a jar to keep bees, grasshoppers, and other lively insects from escaping from the killing bottle when it is opened for putting in other specimens. This cap is made by soldering an incomplete metal cone to a screw cap with the top cut out. A metal tube 34 to 1 inch in diameter is then soldered inside the cone. Chemicals Various chemicals may be used in the bottles for killing agents; two of the best are discussed below. Cyanide.—Calcium cyanide, potassium cyanide, or sodium cyanide may be used. Wrap some granular cyanide (a heaping teaspoonful for small bottles, larger amounts for large bottles) in cellucotton, or place it in a “nest” in cellucotton or a little cloth bag, and put this in the bottom of the bottle. Over this place a plug or several layers of cellucotton or a layer of dry sawdust. Cellucotton is inexpensive and may be purchased at most large drug stores or from supply houses. If the bottle is more than 114 inches in diameter, a 14-inch layer of plaster of paris should be poured in and allowed to harden for a few hours before the bottle is corked. If the bottle is a small one, several disks of clean blotting paper, cut to fit the bottle snugly, may be used in place of the plaster of paris. 6 MISC. PUB. 601, U. 8S. DEPT. OF AGRICULTURE Plaster of paris } Disks of blotting paper Cyanide in cellucotton Cyanide in eellucotton FIGURE 2.—Killing bottles: A, Large, wide-mouth cyanide bottle for large insects ; B, vial-type cyanide bottle for small insects; C, screw-cap top for large cyanide bottle, showing a convenient arrangement to prevent the escape of active specimens. Cyanide is a deadly poison and should be handled with great care. All bottles should be conspicuously labeled ““POISON” and should be kept away from people who do not realize the deadliness of the chemical. The bottom of a cyanide bottle should be taped so that if the bottle is broken the cyanide will not be scattered about. Ethyl acetate-—To make a killing bottle in which to use ethyl acetate (acetic ether), pour a half inch or more of plaster of paris into the bottom of a suitable jar or vial, allow it to set, and dry it thoroughly in an oven. After the plaster of paris is completely dry, saturate it with ethyl acetate, pouring off any excess fluid. The killing bottle is then ready for use and will last for months if kept tightly corked. When it becomes ineffective it can be dried in the oven and recharged. Insects may be preserved in such bottles for an indefinite time without becoming brittle, provided they receive an occasional moistening with ethyl acetate. Ethyl acetate is relatively easy to obtain, and the kill- ing bottles have the obvious advantage of being comparatively safe to use. COLLECTION AND PRESERVATION OF INSECTS 7 Care and Use The killing bottle will last longer and give better results if the fol- lowing simple rules are observed: 1. Before using the cyanide bottle, put in a few strips of soft paper. Ordinary toilet paper is excellent. This will help keep the bottle dry and will keep the specimens from mutilating one another. Change these strips whenever they become soiled or slightly moist. Wipe out the bottle if it becomes moist. 2. Keep a special bottle for moths and butterflies. The scales from these insects will stick to other insects and spoil them. 3. Never put small or delicate insects in the same bottle with large insects such as grasshoppers and large beetles. Beetles are hard to kill and must be left in the killing bottle longer than most other insects. 4. Never overload a bottle, and always remove insects from the cyanide bottle as soon as they are dead. 5. Discard or recharge bottles that no longer kill quickly. Dispose of the con- tents of old cyanide bottles by burning or burying. Many insects should not be killed in a killing bottle but should be placed in 70-percent alcohol or some other fluid. These insects are discussed in more detail later in this bulletin. For these insects the collector should have a supply of small homeopathic vials of various sizes with corks to fit. Figure 3.—Aspirator, or suction bottle: A, Vial-type aspirator assembled; Bb, details of stopper assemblage for vial-type aspirator, showing outlet tube flush with surface of stopper; C, attachment for collecting tiny insects with an ordi- nary aspirator; D, body of tube-type aspirator; H, details of construction to convert an aspirator to the blow type. ASPIRATOR, OR SUCTION BOTTLE The aspirator is a convenient device for collecting small insects, either from the beating net or beating cloth or directly from under stones, bark, etc. Its construction is rather simple and needs little discussion. For the type illustrated in figure 3, A, the following materials are needed: = =x LEE LET eo eee = Ze Ste SF 8 MISC. PUB. 601, U. 8S. DEPT. OF AGRICULTURE 1. A glass vial 1 to 1144 inches in diameter and about 41% inches long. 2. A rubber stopper with two holes in it. 3. Two pieces of metal or plastic tubing, one about 14 inch in diameter and 10 inches long, the other slightly larger and 4 or 5 inches long. 4. A piece of rubber tubing about 3 feet long and big enough to slip onto the larger of the metal or plastic tubes. 5. A small piece of bolting cloth or fine-mesh wire screen. The metal tubes should fit snugly in the holes in the rubber stopper. The shorter metal tube should be bent as indicated so that the rubber tubing will not fold shut when in use. The bolting cloth should be fastened over the end of the larger metal tube as shown; this is to keep the insects from being sucked into the mouth. If wire screen is used it may be soldered to the end of the metal tube. It is desirable, but not necessary, to have the shorter tube come flush with the end of the cork, as in figure 3, B. If metal or plastic tubing is not avail- able or cannot conveniently be bent to suit, glass tubing may be used but has the disadvantage of breaking easily. The length and size of the tubing, as well as the degree of the bends, may be adapted to the user’s convenience. When the aspirator is assembled, place the end of the rubber tub- ing in the mouth, aim the longer tube of the aspirator at a small insect, and suck sharply. The air current will pull the insect into the vial. With a little practice it is possible to collect small insects much more quickly and in better condition this way than by almost any other method. A convenient attachment for collecting thrips, very small flies, beetles, and other insects normally killed in liquid is illustrated in figure 3, C. By means of a short section of rubber tubing a tapered piece of glass tubing 2 or 3 inches long is attached to the intake tube of the ordinary aspirator. A piece of fine-mesh bolting cloth, inserted in the glass tubing’ near the large end, keeps the tiny insects from going on into the aspirator. They can then be blown out into the vial of liquid in which they are to be preserved. This attachment is easily put on and taken off, and having it makes it unnecessary to carry a small aspirator. Some collectors prefer the tube-type aspirator, the body of which is illustrated in figure 3, D. Either the tube-type or the vial-type aspirator may be converted to a blow-type collecting bottle by sub- stituting for the shorter tube, to which the rubber tubing is attached, the attachment illustrated in figure 3, #. This piece of equipment makes use of an air current to create a partial vacuum, and with it in use in the assembled aspirator, the same result is obtained by blowing instead of sucking through the rubber tubing. This type of attachment is essential if the aspirator is to be used to collect insects that emit noxious odors. BEATING CLOTH, OR UMBRELLA Instead of beating vegetation with a net, 1t is sometimes convenient to have a cloth surface over which shrubby plants can be beaten. For this purpose the beating cloth, or umbrella, is suggested. The beating cloth should be about 1 yard square, of durable material, and preferably white. It may be stretched nearly flat by fastening COLLECTION AND PRESERVATION OF INSECTS 9 the corners to a frame made by crossing and fastening together two pieces of light wood, one of which should project a little beyond the corner of the cloth to serve as a handle. The umbrella is used in- verted and should have the handle jointed so that the umbrella may easily be held upside down below branches and bushes. When in use, both the beating cloth and the umbrella are held below the vege- tation while the branches are struck sharply with a club. In this way many insects will be jarred onto the cloth and can be readily captured. These pieces of equipment are also handy when pulling bark from trees and, when so used, will catch many specimens that would other- wise escape. SIFTERS Many insects spend all or part of their lives in ground litter and leafmold. These cannot be captured by ordinary collecting methods, and because they are too active to be caught by hand, or they feign death when disturbed, a sifter should be used. Almost any container with a wire-mesh bottom will serve as a sifter. The size of the meshes in the screen will depend upon the size of the insects sought; for general purposes a screen with eight meshes to the inch will be satisfactory. The screen may be fastened to a wooden frame to make a box-shaped sifter, or it may be attached to a wire hoop, which is then sewed to one end of a cloth sleeve about 12 inches in diameter. In the latter type of sifter it is convenient to have a wire hoop of the same size at the other end of the cloth sleeve to hold it open. Place the leafmold or ground litter in the sifter and shake it gently over a piece of white oilcloth spread flat on the ground. As the insects fall onto the cloth they may be easily captured with an aspirator or tweezers. Many insects feign death and are not easily seen until they move, so the debris on the cloth should not be discarded too quickly. The sifter is especially useful for winter collecting. SEPARATORS The collector who wishes to obtain large numbers of the small insects that are usually found in ground litter will find it advan- tageous to construct a separator (usually called a Berlese funnel by entomologists) for use instead of the sifter. Fundamentally, the separator consists of a funnel over which a sieve containing leafmold or other litter may be placed. The funnel leads into a receptacle containing a liquid preservative, into which the insects fall when driven from the material in the sieve by the progressive drying with a light bulb or some other source of mild heat. Many separators, some very elaborate, have been devised by entomologists, but all rely on the same basic principles. Details of construction may be obtained by writing to some entomological institution. COLLECTING AT LIGHTS Collecting at lights, especially on warm, humid nights, frequently permits the collector to obtain in abundance insects that are captured rarely or not at all by other methods. While light traps, many types of which have been devised, are of use to entomologists for making Se ee. eT ree ae a ESTEE ES CEI SS EIT IO TES 10 MISC. PUB. 601, U. 8S. DEPT. OF AGRICULTURE surveys to determine the abundance of certain insects in restricted regions, their use as a means of obtaining insects for the collection is not recommended because the specimens are too frequently damaged. Insects for the collection should be selected and captured by attend- ing the hght continuously while it is in operation. Although any reasonably bright light will serve, more insects are attracted to blue lights than to other kinds. A convenient method of collecting at a light is to hang up a white sheet so that the light shines upon it, turn up the lower edge to form a trough into which some of the insects will fall, and collect the specimens as they come to the sheet. Many insects may also be collected around street lights and lighted store windows. BAITS AND BAIT TRAPS Baits of many kinds are valuable aids to the collector. One of the best known uses for baits is in “sugaring” for moths. For sugaring, make a mixture of molasses or brown sugar, a little asafoetida, and stale beer, rum, or fermenting fruit juices, and daub it on tree trunks along a route that can be conveniently visited with a lantern or flash- light. As with light collecting, this method is most productive on warm, humid nights. The bait should be applied about dusk and may be visited at intervals all that night and frequently will be found to be attractive to insects on succeeding nights. Moths, ants, and many other insects will be found at the bait. Insects that are attracted to either sweet substances or decaying meat may be captured in simple jar traps. Bait the jar (an olive bottle or a fruit jar will do) with an appropriate bait, and bury it with the open top flush with the surface of the ground. It is fre- quently desirable to set these traps under loose boards or stones lying on the ground. TWEEZERS, FORCEPS, AND BRUSHES The collector will find it advantageous to have available an assort- ment of tweezers and brushes as an aid both in collecting and in handling the specimens after they are dead. Equipment of this kind may be purchased at small cost from most biological supply houses. FIGURE 4.—Tweezers and forceps: A and B, Types of tweezers for handling ordi- nary specimens; C, tweezers for handling unmounted Lepidoptera; D, tweezers for handling living, soft-bodied insects; # and F’, two types of pinning forceps. COLLECTION AND PRESERVATION OF INSECTS Ach Three standard types of tweezers are illustrated in figure 4, A, B, and C. ‘Tweezers of the straight-pointed type are ideal for bending the tips of card points on which to mount small specimens and w ill be useful for many other purposes. However, some workers prefer the curved tips for handling specimens. The a eezers shown in figure 4, C, are best for handling ‘dead butterflies, as the tips will not break thr ough the wings so readily as will the points of the tweezers shown in A and B. Figure 4, ), illustrates a pair of tweezers that may be made from two pieces ‘of flexible steel spring. These are ideal for handling living or dead specimens with very soft bodies. A few small camel’s-hair brushes, sizes 0 to 2, are handy for picking up small insects that might be crushed if handled with tweezers. Moisten the tip of the brush on the tongue or in the liquid preserva- tive, touch the specimen with the brush, and you can transfer it safely to the collecting vial. If brushes are not available, the moistened end of an ordinary flat toothpick is a satisfactory substitute. Figure 4, Z, illustrates a type of dental forceps that is recommended as a pinning forceps. The curved tips permit the pin to be grasped below the pin labels, and thus even very slender pins can be set firmly into cork without bending. REARING Whenever possible, the collector should avail himself of the oppor- tunity to rear insects, for by so doing he may secure many insects otherwise obtained only rarely. In addition, the specimens will fre- quently be in much better condition than collected material, and there is an opportunity to make valuable observations on the biology of the species reared. If abundant material is available for rearing, it is always advisable to preserve a few specimens of each of the various stages according to instructions given later in this bulletin, so that the complete life history of the species will be represented. If only a few specimens are being reared, the shed skins of the specimens should be preserved, as these are of value also. To rear specimens successfully the natural conditions under which the immature insects were found should be simulated as closely as possible in the rearing cages. Insects that feed on living plants may be caged over potted plants or fed frequently with fresh material from their host plant. With a little ingenuity a suitable cage can be prepared; the important thing is to have it tight enough to keep the insects in and yet provide for sufficient ventilation so that the container will not “sweat.” Some loose, slightly moist soil and ground litter should be provided in case the insect is one that pupates in or on the ground. Insects that feed on decaying animal matter should also have the cage provided with slightly moist soil or sand. Insects that infest seeds and those that cause plant galls may be reared merely by enclosing the seeds or galls in a tight container. Such material should not be permitted to become too dry; neither should it be kept moist, else the material and the specimens will mold. It is a good plan to insert the open end of a glass vial through a hole in the container; then, if the container is dark, when the specimens a MISC. PUB. 601, U. S. DEPT. OF AGRICULTURL emevge they will be attracted to the light, enter the vial, and can be easily removed and killed. Tiny parasitic wasps may be reared from their hosts in this manner. A cardboard ice-cream container is excel- lent for this type of rearing. Adult moths, butterflies, beetles, and many other insects may be obtained by collecting pupae and caging them until the specimens emerge. In this way the best specimens of moths and butterflies may be secured. Always permit the reared specimen to harden and color completely before killing it, but do not leave it in the cage so long that it will damage itself in trying to escape. Cages should always be placed where they will be safe from ants. Very often bark and wood infested by boring insects, such as beetles, are found. If these are placed in glass or metal containers, excellent specimens of the adults may be obtained. Cages of wood and card- board should be avoided for obvious reasons. Such material can often be collected and caged during the winter months, the period of effec- tive field collecting being thus extended. HOW TO KILL AND PRESERVE SPECIMENS The method of killing and preserving to be used depends upon the kind of insects involved. No one method is satisfactory for all speci- mens, and it is necessary for the collector to have some knowledge of what is being collected in order properly to care for the material. Frequently it is desirable to kill in liquid any specimens that will later be pinned for the collection. The best general liquid killing and preserving agent, which should always be used unless some other preservative is especially recommended, is 70- to 75-percent grain (ethyl) alcohol. Formalin, which is frequently used as a preserva- tive for biological specimens, is not recommended as a preservative for insects because it hardens the tissues and makes the specimens difficult to prepare for study. In the discussion that follows, alcohol, unless otherwise indicated, means 70- to 75-percent grain alcohol. The procedure to be followed for all insects killed in alcohol but later mounted dry is as follows: 1. Kill in alcohol. 2. Dehydrate in 100-percent alcohol (200 proof, also called absolute alcohol). This step takes from 1 to 24 hours, depending on the size of the specimens. 3. Degrease in xylene (zylol) or benzene (benzol). This step requires about the same length of time as the dehydration. If specimens retain a milky film in the xylene they have not been completely dehydrated. 4. Remove from xylene, dry, and mount. Specimens killed in the ethyl acetate killing bottle, but which con- tain considerable fatty tissue (lipoids), should be degreased before being mounted. Any of a number of lipoid solvents may be used, the most satisfactory of which is ordinary commercial sulfuric ether. Soak the specimens in the ether bath until the fluid ceases to become yellow from the dissolved oils, changing the fluid if necessary. The length of time necessary for complete degreasing will vary from a day to a week, depending upon the size and number of specimens, their fat content, and the volume of ether used. A wad of absorbent tissue or filter paper should be placed in the bottom of the container COLLECTION AND PRESERVATION OF INSECTS 13 to absorb waste that accumulates and which might otherwise cling to the specimens. Ether has the disadvantage of being highly inflammable and must be used with great care. Other solvents which may be used are chloro- form, benzene, xylene, and diethyl carbonate. If chloroform is used, the specimens must be held submerged by a wire screen. After being degreased, specimens should be transferred to a clean pad of absorbent tissue and their appendages arranged; after they are sufficiently dry they may be mounted. Specimens that contain but little fatty tissue (lipoids), and hence do not ordinarily become greasy, may be killed in the cyanide jar or the ethyl] acetate killing bottle and mounted without further prep- aration. Pinned specimens that have become greasy owing to the decomposition of body fats may be degreased by being put in an ether or chloroform bath for a few hours. Other killing agents, such as carbon tetrachloride, ether, chloroform, and benzene may be used, but each has some objectionable features, and they are not recommended for general use. Some insects, such as scale insects, aphids, lice, thrips, and other minute forms, can be satisfactorily studied only after they are mounted on a microscope slide. These insects should be killed and preserved according to the instructions which follow, but the proper preparation of slide mounts is a task requiring considerable equipment and experi- ence, and slide preparations should not be attempted without the aid of specific instructions, which are usually different for different groups of insects. The following outline gives instructions for killing and preserving the commoner types of insects and also indicates the usual method of mounting for study. Methods of mounting specimens on pins are discussed in detail later in this bulletin. The steps between killing and mounting specimens killed in alcohol or the ethyl acetate killing jar have been outlined above and are not repeated here. Descriptions and illustrations of common representatives of most of these insect groups are given under Recognition of Material, page 26. Anoplura (sucking lice): Kill and preserve in alcohol; mount on slides. Coleoptera (beetles) : Kill in alcohol or ethyl acetate vapor; mount on pins. Collembola (springtails) : Kill and preserve in alcohol; mount on slides. Corrodentia (booklice) : Kill and preserve in alcohol. Dermaptera (earwigs) : Kill in cyanide, ethyl acetate vapor, or alcohol; mount on pins. Diaiees (flies) : Kill in cyanide, except minute forms, such as eye gnats and fungus gnats, which should be killed in alcohol; mount on pins. Ephemeroptera (Mayfiies) : Kill and preserve in alcohol. Hemiptera (true bugs and their allies): Kill in cyanide, ethyl acetate vapor, or alcohol, except the immature stages, aphids, scale insects, and Aleyrodidae (whiteflies) ; mount on pins. Nymphs should be killed in alcohol and mounted on pins. Aphids should be killed in alcohol and mounted on slides. Scale insects and whiteflies on host material should be preserved dry, but if they are not on host material they should be preserved in alcohol; mount on slides. Hymenoptera (bees, wasps, ants, etc.) : Kill in cyanide, except ants, gall wasps, and small parasitic forms, which should be killed in alcohol; mount on pins. Isoptera (termites) : Kill and preserve in alcohol. Lepidoptera (moths and butterflies) : Kill in cyanide; mount on pins. Mallophaga (biting lice): Kill in alcohol; mount on slides. ea Tae era 14 MISC. PUB. 601, U. S. DEPT. OF AGRICULTURE Mecoptera (scorpion flies) : Kill in cyanide; mount on pins. Neuroptera (lacewing flies, ant lions, etc.) : Kill in cyanide; mount on pins. Odonata (dragonflies) : Kill in cyanide; mount on pins. Orthoptera (grasshoppers, crickets, roaches) : Kill in cyanide; mount on pins. Plecoptera (stoneflies) : Kill and preserve in alcohol. Siphonaptera (fleas) : Kill in alcohol; mount on slides. Thysanoptera (thrips): Kill in a liquid made of 8 parts 95-percent alcohol, 5 parts distilled water, 1 part glycerin, and 1 part glacial acetic acid; mount on slides. Thysanura (silverfish and their allies) : Kill and preserve in alcohol. Trichoptera (caddisflies) : Kill in cyanide; mount on pins. Zoraptera: Kill and preserve in alcohol. Larvae of insects should be killed in boiling water and allowed to remain in the water from 1 to 5 minutes, according to size, then preserved in alcohol. Centipedes, millipedes, mites, spiders, ticks, and other small arthropods, although they are not insects, are frequently handled by entomologists. All these should be killed and preserved in alcohol. The smaller forms are usually mounted on slides. CARE AND HANDLING OF UNMOUNTED SPECIMENS © It is frequently impracticable to mount all collected specimens soon after they are killed, and some method of caring for them so they will not be broken must be used. Specimens collected in liquid may be preserved in the hquid indefinitely without injury, the only pre- caution being to keep plenty of fluid in the container. Specimens that are killed in the ethyl acetate bottle and are intended for the ether bath may also be preserved indefinitely in a container with just enough ethyl acetate to keep them from drying. Specimens that are killed in cyanide and are to be mounted without further treatment will soon become dry and brittle. Such material should be placed in paper pill boxes between layers of cellucotton cut to fit the box and packed tightly enough so that the specimens will not shift about, but not pressed down enough to flatten or distort the specimens. The pill box should be filled with layers of cellucotton, even though all the layers are not needed for specimens. Cotton should not be used, as legs and antennae catch on the fibers and are apt to be broken off. Medium-sized and small Lepidoptera should be packed one specimen to a layer of cellucotton. Large Lepidoptera, Odonata, and other insects with large wings and relatively small bodies should be placed in envelopes or folded “triangles,” which may then be packed between layers of cellucotton. The method of folding a rectangular piece of paper to form a “triangle” is shown in figure 5. The speci- men should be placed in the folded triangle in the position shown in fioure 5, B. When storing unmounted specimens, do not forget to write the collection data on the pill box or on the end of the envelope or “triangle.” HOW TO MOUNT INSECTS Specimens are mounted to facilitate handling and study, and their value increases with the convenience with which they may be exam- ined and compared with specimens of the same or related species. As a result of years of experience by many workers there have been COLLECTION AND PRESERVATION OF INSECTS 15 Figure 5.—Method of folding a rectangular piece of paper to form a triangular envelope for large-winged insects: A, Correct shape of unfolded paper, showing where the folds should be made and the sequence of the first three folds; B, “triangle” almost completely folded, showing correct position of the enclosed butterfly. developed standard pinning practices, designed to avoid injury to the specimens and to expedite study. Although methods of preparing specimens are constantly being improved, currently accepted prac- tices should be observed in the interest of uniformity until the superi- ority of other methods has been clearly demonstrated. DIRECT PINNING Ordinary household pins are too short and thick and should not be used for pinning insects. Insect pins, which may be purchased from supply houses, should be of good-quality spring steel and thor- oughly japanned so as to be nearly rustproof. They may be obtained in numbered sizes and different lengths suitable for pinning insects of various sizes. For most purposes No. 2 or No. 3 pins 34 mm. long will be found satisfactory, although a smaller size, No. 1, may occa- sionally be desirable for small flies, and larger and longer pins, such as No. 4 or No. 5 pins 37 or 89 mm. long, are better for large-bodied moths, beetles, and cicadas. A comparison of a millimeter scale with the more familiar inch scale is given in figure 6. Ficure 6.—Comparison of inch and millimeter scales. A centimeter equals 10 millimeters. Medium-sized and large insects should be pinned vertically through the body with a pin of appropriate size. Figures 7 and 8 illustrate some right and wrong pinning practices. Before pinning a specimen it is well to examine the under side so as to be sure that the pin will not break off a leg where it comes through. The standard methods for pinning the commoner types of insects are as follows: SS a Ce ae oe Se EE SS SS SS EE a = 16 MISC. PUB. 601, U. S. DEPT. OF AGRICULTURE 1. Grasshoppers, katydids, ete.: Pin through the back part of the thorax to the right of the middle line (fig. 9, A) 2. Stinkbugs and other large Hemiptera: Pin through the scutellum to the right of the middle line (fig. 9, C). 3. Bees, wasps, and flies: Pin through the thorax between or a little behind the bases of the forewings and to the right of the middle line (fig. 9, D). 4. Beetles: Pin through the right wing cover near the base (fig. 9, #). 5. Moths, butterflies, dragonflies, and damselflies: Pin through the middle line of the thorax at the thickest point or between or a little behind the bases of the forewings (fig. 9, F, G). FIGURE 7.—Illustration of right and wrong methods of pinning: A, Correct height and position for specimen; B, insect too low on the pin; @, insect tilted on the pin. right wro wrong A B C Figure 8.—Illustration of right and wrong methods of pinning: A, Correct height and position for specimen; B, insect too high on the pin; C, insect tilted on the pin. rs : The height of the specimen on the pin will depend somewhat on the size of the specimen. In general, there should be enough room at the top of the pin so that it may be handled without the fingers touching the specimen. With a little practice this may be judged accurately; if uniformity is desired, the specimen may be adjusted to the desired height on the pin by using the pinning block shown in fioure 10. After being pinned, and before being permitted to dry (or after being thoroughly relaxed if already dried), the legs, wings, and antennae of the specimen should be properly arranged so they are visible for study. The correct arrangement of legs and antennae for grasshoppers and related forms is shown in figure 9, B. With many insects, such as beetles, bugs, flies, and bees, it is only necessary to arrange the legs and antennae and they will stay in place. With grasshoppers, however, it 1s usually necessary to pin the specimens COLLECTION AND PRESERVATION OF INSECTS LZ close to the edge of a box so that other pins to hold the legs in place may be thrust into the sides of the box at various angles. With some specimens, such as wasps and long-legged flies and bugs, the legs and abdomen may be kept in place until dry by pushing a piece of stiff paper up on the pin beneath them. Moths, butterflies, and sometimes grasshoppers, dragonflies, and cica- das, should have the wings on one or both sides spread. For this purpose a spreading board is necessary. The construction and use of the spreading board is discussed on page 19. i a SL MS) are ee | |_| We = het = Figure 9.—Examples of correct pinning methods for common insects; the black spots show where the pins should go. A, Grasshopper and related Orthoptera, showing how wings should be spread; B, side view of a grasshopper, showing position of legs and antennae; C, a stinkbug, an example of the order Hemip- tera, showing method of pinning large bugs; D, a bee, order Hymenoptera, to show where bees, wasps, and flies should be pinned; HE, a May beetle, order Coleoptera, Showing method of pinning beetles; F, G, butterfly and moth, order Lepidoptera, showing location of pin and position of wings and antennae. FicuRE 10.—Pinning block for adjusting specimens and labels to a uniform height on the pin. 18 MISC. PUB. 601, U. S. DEPT. OF AGRICULTURE DOUBLE MOUNTS Small insects which cannot be pinned directly through the body with regular insect pins should be mounted on card points or on “minuten nadeln.” Card points are slender triangles of paper. These are pinned through the broad end with a regular insect pin (No. 2 or 8), and the specimen is glued to the point, as illustrated in figure 11, A. The card points should be pinned at the height obtained by using the highest step on the pinning block (fig. 10). Card points may be cut with — scissors from a strip of paper three-eighths inch wide, but a punch, FicurE 11.—Double mounts for small insects: A, Position of card point and labels on the pin; B, details of attachment of specimen to card point; C, small moth, order Lepidoptera, pinned with a “minute nadel”’ to a block of pith on a regular insect pin; D, a mosquito, order Diptera, pinned with a “minute nadel” to a block of cork on a regular insect pin; #, method of attaching an inflated larva to a regular insect pin by twisting fine wire around a block of cork. obtainable from supply houses, makes better and more uniform points. A good-quality linen ledger paper should be used; ‘“‘substance 36” is | recommended. ‘To fasten the specimen to the point ordinary glue may be used, but it is not recommended because it tends to become brittle. Some of the clear acetate cellulose cements, such as ‘‘Ambroid,” which may be purchased in small quantities at variety stores, are satisfactory. An adequate supply may be made by dissolving a trans- parent resin toothbrush handle in a small amount of banana oil (amyl acetate). Pure white shellac is also fairly satisfactory but may be difficult to obtain. Whatever adhesive is used, it should not be per- | COLLECTION AND PRESERVATION OF INSECTS 19 mitted to get so thick that it “strings,” and only a small amount should be used. To mount most insects the tip of the card point should be bent down at a slight angle so that when the insect is in an upright posi- tion the bent tip of the point fits against the side of the insect (fig. 11, B). Only a very small part of the point should be bent; a little | practice will make it easy to judge how much of the point should be bent and at what angle to fit the particular specimen that is being | mounted. Most insects that are mounted on points should be attached to the point by the rzght side, although there are a few exceptions to this rule. A convenient method is to arrange the insects on their backs or left sides with their heads toward the worker; then, with the pin held in the left hand, touch a bit of adhesive to the bent point and apply it to the right side of the insect. If the tip of the point can be slipped between the body of the insect and an adjacent leg, a stronger mount will result. The insect should be attached to the point by the side of the thorax, not by the wing, abdomen, or head. Some insects, too heavy to be held on the point by the adhesive and not large enough to be pinned with regular pins, may be attached to | card points by puncturing the right side at the place where the card | point would normally be placed and inserting in this puncture the tip of an unbent card point with a little adhesive on it. For punc- turing specimens a needle ground to make a small, sharp scalpel is best. To conserve pins and space in the collection it is sometimes advan- tageous to mount two or three specimens of the same species on card points on a single pin. These may be arranged one below the other at different levels, or may be fanned out at the same level. “Minuten nadeln” are very small steel pins without heads which are used to pin small insects on a piece of cork or pith, which is then pinned on a regular insect pin, as illustrated in figure 11, C, D. As with direct pinning, insects mounted on double mounts should be prepared according to standard practices. For the commoner groups these are as follows: 1. Beetles, bugs, leafhoppers, ete.: Mount on card points with the tip bent down and attached to the right side of the specimen (fig. 11, A, B). 2. Small parasitic wasps: Mount on unbent card points with the adhesive ap- plied to the left side of the specimen and the feet toward the pin. 3. Small moths: Mount on “minuten nadeln” thrust through the middle of the thorax from above and with the abdomen of the specimen toward the insect pin (fiosstalerG:); 4, Small flies and mosquitoes: Pin with “‘minuten nadeln” through the side of the thorax with the right side of the specimen toward the insect pin (fig. 11, D). Some workers prefer small flies fastened directly to regular insect pins by a bit of adhesive applied to the right side of the specimen. INFLATION OF LARVAE | Although inflated larvae are not recommended as specimens in- tended for critical scientific study, it is sometimes desirable to inflate larvae for exhibition purposes. To do this the following simple equipment is needed : 20 MISC. PUB. 601, U. S. DEPT. OF AGRICULTURE - 1. A piece of finely drawn glass tubing furnished with clips held in place by a small rubber band (fig. 12). 2. A tin can or box to serve as an oven, and a spirit lamp or some other heating unit. Place the larva on a clean blotter and force the body contents out by gently rolling a piece of glass tubing or round pencil from just back of the head to the end of the abdomen, being careful not to break off spines and hairs. Insert the drawn end of the glass tubing into the anal opening of the larva and secure it in place with the clips. Blow gently into the glass tubing so that the larva is distended to its normal size but not distorted, and bake it in the oven until dry, blowing the specimen meanwhile so it does not collapse, and being careful not to scorch it. When it is thoroughly dry, carefully remove it from the glass tubing by means of a fine dissecting needle and mount it on a twisted wire as shown in figure 11, #. This kind of mounting is quite firm if the twisted wire extends inside the larva for about two-thirds the length of the specimen. Figure 12.—Tip of drawn glass tubing, showing clips holding larva in place for inflation. RIKER MOUNTS Occasionally it is desirable to arrange specimens for exhibition in such a way that they may be freely handled without injury. This may be done in various ways, but the method most frequently em- ployed is to use the so-called Riker mount. This consists of a flat cardboard box filled with cotton on which the unpinned specimens are placed and covered with a glass top which holds them in place. Riker mounts may be purchased from most supply houses. SPREADING BOARDS AND BLOCKS The construction and use of the spreading board are illustrated in figure 18. The active collector will find it advantageous to have sev- eral boards with the middle grooves of different widths to accommo- date insects of various sizes, but for general purposes a board made from the following materials will be satisfactory: 1. A hardwood base, 14 by 4 by 12 inches. 2. Two hardwood endpieces, % by 34 by 4 inches. 3. Two softwood toppieces, 34 by 1% by 12 inches. 4. One flat strip of cork, 14 by 1 by 11 inches. When assembled as illustrated, the softwood toppieces leave a groove one-quarter inch wide. On the underside of these the cork strip is glued so that it covers the space between the toppieces. Specimens must be thoroughly relaxed for spreading; otherwise they will be broken. Figure 13 shows the wings on the left side of the specimen spread in the proper manner. ‘The first step in spread- ing the wings, after pinning the specimen in the groove at the proper height, is shown on the right side of the board in figure 13. To com- COLLECTION AND PRESERVATION OF INSECTS 21 F'iauRE 13.—Portion of a spreading board, showing construction of the board «2: steps in the process of spreading the wings and arranging the abdomen ald antennae of a butterfly, order Lepidoptera. plete the process, hold the strip of semitransparent paper covering the wings gently with the fingers of one hand and pull the wings forward with an insect pin until the hind margin of the forewing is at right angles to the body of the insect. The hind wing should then be brought forward until its front margin is just under the hind margin of the forewing. Pin both wings in place with plenty of pins arranged around them, not through them. The abdomen and antennae should also be held in place by pins. The paper strips hold- ing the wings in place should be of fairly thin, not stiff, paper. The spreading block is a modification of the spreading board, de- signed to accommodate very small moths and other small insects. its construction and use are illustrated in figure 14. The top of the block We \< eal \ Ni8 \ { S\N Figure 14.—Construction and use of the spreading block for small insects. (neta errs REECE Ee = FS am * oa hi EEE SDE SRE EES TRS 22 MISC. PUB. 601, U. 8. DEPT. OF AGRICULTURE should be flat and smooth; the groove may be of any desired width. A hole should be drilled through the center of the block to permit the insect pin or “minute nadel” to extend below the level of the groove, and the bottom of the groove should be packed with cellu- cotton or fitted with a strip of soft pith. When insects are mounted on the spreading block, thin, flat, rectangular pieces of celluloid are used to hold the wings in place. After the wings are properly ar- ranged, each side of the block should be wrapped, but not too tightly, with a piece of thread, as illustrated. The spreading of very small insects is a task requiring considerable skill and patience. Specimens should be left on the spreading board or block until thoroughly dry. For large insects this requires 2 or 3 weeks; smaller specimens will dry in less time. During this time they should be stored in pestproof containers. Do not forget the collection-data label, which should be asociated with the specimen at all times. RELAXING JARS Insects that have dried after being killed in the cyanide bottle must be relaxed before they are mounted. This can easily be done in a relaxing jar made as follows: Into a wide-mouth jar or can with a tight cover put an inch or two of clean sand; saturate the sand with water to which a few drops of phenol (carbolic acid) have been added to keep mold from growing; cover the sand with a piece or two of cardboard cut to fit the jar, and it is ready for use. Specimens must not come in direct contact with the water and should not be left in the relaxer too long or they will be spoiled. From 1 to 3 days is usually sufficient. A relaxer should not be left where it will get too warm, or it will “sweat” on the inside. LABELING THE SPECIMENS During the course of preparation and mounting, specimens should have associated with them a temporary label giving essential informa- tion as to date and place of collection; and before they are put away in the collection they should be labeled with a permanent label, which is either pinned below the specimen if the specimen is mounted, or is placed in the vial if the specimen is preserved in liquid. These labels are usually small, and for that reason the data that can be given must be restricted to the most important information. Any additional information about the specimen or specimens should be kept in field notes, which can be associated with the proper material by means of lot numbers or some other convenient system. When specimens are sent for identification they should always be accompanied by all available information. WHAT INFORMATION IS ESSENTIAL The following information should be given on the label or labels for each specimen: 1. Locality: The place of collection should be given as exactly as possible and should be so designated that it can be found on a good map. If the place of collection does not appear on a map, it may be given in terms of the approximate direction and distance from some landmark or town. | COLLECTION AND PRESERVATION OF INSECTS 23 2. Date: The day, month, and year should be given. 3. Collector: The collector should be indicated as a possible source of further information omitted from the label. 4. Source: If known, the host, food plant, or material attacked should be indicated. ne If a system of lot numbers is used to associate specimens with field notes, of course the lot number should appear on the label also.