Chapter I: Part 1

STATE OF ILLINOIS
DEPARTMENT OF REGISTRATION AND EDUCATION

HOW TO COLLECT
AND
PRESERVE INSECTS

H. H. ROSS

_Printed by Authority of the State of Illinois_
NATURAL HISTORY SURVEY DIVISION
George Sprugel, Jr., Chief

Circular 39 Urbana November, 1966
(Eighth Printing)

STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION
BOARD OF NATURAL RESOURCES AND CONSERVATION

John C. Watson, _Chairman_; Thomas Park, Ph.D., _Biology_; L. L.
Sloss, Ph.D., _Geology_; Roger Adams, Ph.D., D.Sc., _Chemistry_; Robert
H. Anderson, B.S.C.E., _Engineering_; Charles E. Olmsted, Ph.D.,
_Forestry_; W. L. Everitt, E.E., Ph.D., _Representing the President of
the University of Illinois_; Delyte W. Morris, Ph.D., _President of
Southern Illinois University_.

NATURAL HISTORY SURVEY DIVISION, Urbana, Illinois
SCIENTIFIC AND TECHNICAL STAFF
George Sprugel, Jr., Ph.D., _Chief_
Herbert H. Ross, Ph.D., _Assistant Chief_
Robert O. Watson, B.S., _Assistant to the Chief_

Section of Economic Entomology
William H. Luckmann, Ph.D., _Entomologist and Head_
Willis N. Bruce, Ph.D., _Entomologist_
Ronald H. Meyer, Ph.D., _Associate Entomologist_
James E. Appleby, Ph.D., _Associate Entomologist_
Robert D. Pausch, Ph.D., _Assistant Entomologist_
Ralph E. Sechriest, Ph.D., _Assistant Entomologist_
Delmar Broersma, Ph.D., _Assistant Entomologist_
Joseph V. Maddox, Ph.D., _Assistant Entomologist_
Edward J. Armbrust, Ph.D., _Assistant Entomologist_
Dannel McCollum, B.A., _Technical Assistant_
Gregory P. Marsh, B.S., _Technical Assistant_
Sue E. Watkins, _Junior Scientific Assistant_
H. B. Petty, Ph.D., _Entomologist in Extension_[1]
Stevenson Moore, III, Ph.D., _Entomologist in Extension_[1]
Roscoe Randell, M.S., _Technical Assistant in Extension_[1]
Clarence E. White, B.S., _Technical Assistant in Extension_[1]
Stanley Rachesky, M.S., _Technical Assistant in Extension_[1]
D. E. Kuhlman, M.S., _Technical Assistant in Extension_[1]
Amal C. Banerjee, Ph.D., _Research Associate_[1]
Jean G. Wilson, B.A., _Research Associate_[1]
Ranu Banerjee, B.A., _Research Assistant_[1]
Ayten Hatidoglu, B.S., _Research Assistant_[1]
Keun S. Park, M.S., _Research Assistant_[1]
Keturah Reinbold, M.S., _Research Assistant_[1]

Section of Faunistic Surveys and Insect Identification
H. H. Ross, Ph.D., _Assistant Chief and Head_
Milton W. Sanderson, Ph.D., _Taxonomist_
Lewis J. Stannard, Jr., Ph.D., _Taxonomist_
Philip W. Smith, Ph.D., _Taxonomist_
Leonora K. Gloyd, M.S., _Associate Taxonomist_
Wallace E. LaBerge, Ph.D., _Associate Taxonomist_
Robert T. Allen, M.S., _Technical Assistant_
Bernice Sweeney, _Technical Assistant_
Bess White, A.B., _Technical Assistant_
John D. Unzicker, Ph.D., _Research Assistant_[1]

Section of Aquatic Biology
George W. Bennett, Ph.D., _Aquatic Biologist and Head_
William C. Starrett, Ph.D., _Aquatic Biologist_
R. W. Larimore, Ph.D., _Aquatic Biologist_
David H. Buck, Ph.D., _Associate Aquatic Biologist_
Robert C. Hiltibran, Ph.D., _Associate Biochemist_
Donald F. Hansen, Ph.D., _Associate Aquatic Biologist_
William F. Childers, Ph.D., _Assistant Aquatic Biologist_
David L. Thomas, B.S., _Research Assistant_
Maryfran Martin, _Technical Assistant_
Claude Russell Rose, _Field Assistant_
Dennis Dooley, _Field Assistant_
Charles F. Thoits, III, B.A., _Research Associate_[1]
David Krulac, _Project Assistant_[1]

Section of Applied Botany and Plant Pathology
J. Cedric Carter, Ph.D., _Plant Pathologist and Head_
J. L. Forsberg, Ph.D., _Plant Pathologist_
Robert A. Evers, Ph.D., _Botanist_
Robert Dan Neely, Ph.D., _Plant Pathologist_
E. B. Himelick, Ph.D., _Plant Pathologist_
Walter Hartstirn, Ph.D., _Assistant Plant Pathologist_
D. F. Schoeneweiss, Ph.D., _Assistant Plant Pathologist_
David Russell Vance, _Technical Assistant_
Robert J. Slattery, B.S., _Technical Assistant_
Robert S. Perry, B.S., _Technical Assistant_
Betty S. Nelson, _Technical Assistant_
Sylvia P. Brockstein, M.S., _Technical Assistant_

Section of Wildlife Research
Glen C. Sanderson, Ph.D., _Wildlife Specialist and Head_
F. C. Bellrose, B.S., _Wildlife Specialist_
H. C. Hanson, Ph.D., _Wildlife Specialist_
Richard R. Graber, Ph.D., _Wildlife Specialist_
Ronald F. Labisky, M.S., _Associate Wildlife Specialist_
William R. Edwards, M.S., _Associate Wildlife Specialist_
William W. Cochran, JR., _Assistant Wildlife Specialist_
Robert E. Greenberg, M.S., _Research Assistant_
Helen C. Schultz, M.A., _Technical Assistant_
Lucinda Janis, _Technical Assistant_
Robert D. Crompton, _Field Assistant_
Ronald Duzan, _Laboratory Assistant_
Mary Ann Johnson, _Laboratory Assistant_
William J. Francis, Ph.D., _Research Associate_[1]
Jack A. Ellis, M.S., _Research Associate_[1]
James A. Bailey, Ph.D., _Research Associate_[1]
Gerald G. Montgomery, M.S., _Research Associate_[1]
William L. Anderson, M.A., _Research Associate_[1]
George B. Joselyn, M.S., _Research Associate_[1]
Gerald L. Storm, M.S., _Field Ecologist_[1]
Ronald L. Westemeier, B.S., _Research Associate_[1]
Stanley L. Etter, M.S., _Research Assistant_[1]
Robert E. Hawkins, B.S., _Research Assistant_[1]
Jeffrey C. Hanson, M.S., _Research Assistant_[1]
Keith T. Dauphin, _Project Assistant_[1]

Section of Publications and Public Relations
Owen F. Glissendorf, M.S., _Technical Editor and Head_
Robert M. Zewadski, M.S., _Associate Technical Editor_
Nancy K. Ginzel, B.S., _Assistant Technical Editor_
Wilmer D. Zehr, _Technical Photographer_
William L. Taylor, _Technical Assistant_

Technical Library
Doris F. Dodds, B.A., M.S.L.S., _Technical Librarian_
Patricia F. Stenstrom, B.A., M.S.L.S., _Assistant Technical Librarian_

CONSULTANTS: Herpetology, Hobart M. Smith, Ph.D., _Professor of Zoology, University of Illinois_; Parasitology, Norman D. Levine, Ph.D., _Professor of Veterinary Parasitology and Veterinary Research, University of Illinois_; Wildlife Research, Willard D. Klimstra, Ph.D., _Professor of Zoology and Director of Cooperative Wildlife Research, Southern Illinois University_; Statistics, Horace W. Norton, Ph.D., _Professor of Statistical Design and Analysis, University of Illinois_.

[1]Employed on cooperative projects with one of several agencies:
University of Illinois, Illinois Agricultural Extension Service,
Illinois Department of Conservation, National Science Foundation,
United States Department of Agriculture, United States Fish and
Wildlife Service, United States Public Health Service, and others.

_This paper is a contribution from the Section of Faunistic Surveys
and Insect Identification._
(33711--10M--10-66)30

Where to Collect 1
What to Use 2
Nets 3
Killing Bottles 6
Aspirators or Suckers 9
Sifter 12
Berlese Funnel 12
Equipment for Collecting Aquatic Insects 16
How to Handle Unmounted Specimens 17
Temporary Cases 17
Relaxing Boxes and Jars 19
How to Mount and Preserve Specimens 20
Preservation by Pinning 20
Spreading Board for Moths and Butterflies 24
Preservation in Fluid 26
How to Label the Specimens 26
Housing the Collection Permanently 27
Insect Boxes 27
Precaution Against Pests 27
The Insect World 28
How to Identify Specimens 34
Synopsis of Illinois Insect Orders 35
Primitive Wingless Insects 35
Diplura 36
Protura 36
Collembola 36
Microcoryphia 36
Thysanura 38
Primitive Winged Insects 38
Ephemeroptera 38
Odonata 38
Folding-Wing Insects 40
Cursoria 42
Isoptera 43
Orthoptera 43
Dermaptera 44
Plecoptera 45
Zoraptera 45
Corrodentia 45
Phthiraptera 45
Mallophaga 47
Anoplura 47
Thysanoptera 47
Hemiptera 48
Megaloptera 52
Neuroptera 52
Coleoptera 53
Hymenoptera 54
Mecoptera 55
Trichoptera 57
Lepidoptera 58
Diptera 60
Siphonaptera 61
Relatives of Insects 62
Isopoda 62
Amphipoda 62
Scorpionida 64
Pseudoscorpionida 64
Phalangida 64
Araneida 65
Acarina 65
Diplopoda 66
Chilopoda 67
The State Insect Collection 67
Reports on Illinois Insects 69
Useful Books 70
How to Ship Specimens 70
Where to Buy Supplies 71

_Printed by Authority of the State of Illinois, Ch. 127. IRS, Par.
58.22._

HOW TO COLLECT AND PRESERVE INSECTS

H. H. ROSS

With rather simple equipment, the amateur as well as the trained entomologist can make a worthwhile collection of insects.

The making of such a collection may have educational and recreational as well as scientific values. Developing this hobby is one of the finest ways for students, especially those in agricultural districts, to become acquainted with the large number of injurious and beneficial insects that they encounter about the home and in the fields. High school classes in biology find excellent laboratory material in the many insects available for rearing and study. Both old and young collectors find a great deal of pleasure in working with the showy and beautiful insects, such as beetles, moths, and butterflies; the satisfaction derived comes both from having relaxation from the day's work and from making real contributions to scientific knowledge. Many entomological museums welcome the opportunity to examine carefully prepared and labeled collections. These collections supply distribution records for insect species, in addition to other information of value to technical entomologists. Also, the amateur collector profits from his contact with specialists who can help him identify his specimens and advise him at any stage of his work.

It is hoped that this circular will show how easy it is to make a start in insect collecting and will give the student helpful ideas on how and where to begin.

WHERE TO COLLECT

In late spring, in summer, and in early fall, insects are very abundant in fields and woods, and large numbers of them may be caught by sweeping through the grass and branches with a strong insect net. Flowers of all descriptions are favorite visiting places of many bees, flies, beetles, and other insects, and will afford good collecting. Woods along the banks of streams, open glades in deep woods, and brush along forest edges offer some of the best opportunities for collecting by the sweeping method.

In early spring, when insects can be taken only sparingly in the open, the collector frequently finds sheltered hollows where they may be caught in large numbers. A certain kind of insect may live only on a certain kind of plant, and to obtain the insect the collector must search or sweep the plant, called the host plant.

Many obscure places harbor insects seldom found elsewhere. Among these are leaf mold and debris on the surface of the soil, particularly in woods; rotten logs and stumps, which should be turned over to reveal insects that hide under or around them, and then carefully searched or torn apart for others that live inside; in, under, and around dead animals; under boards and stones.

Trees sometimes yield valuable specimens. If part of a tree, under which has been spread a large white sheet, is struck with a heavy, padded stick, many insects, such as weevils, will fall to the sheet and "play possum." They can be picked off quite easily.

Lights attract large numbers of certain nocturnal insects, such as June beetles and many kinds of moths; at night these insects may be collected at street or porch lights, on windows and screens of lighted rooms, or at light traps put up especially to attract them. Swarms of aquatic insects come to street lights of towns along rivers, sometimes in such numbers as to pile up in a crawling mass under each light. Collecting at this source is best on warm, cloudy nights; wind or cold keeps most nocturnal insects fairly inactive. Different species of moths and beetles visit the lights in different seasons so that collecting by this method alone yields many kinds of insects.

Insects that live in the water may be collected with heavy dip nets swept through the water at various levels and through the mud and debris at the bottom. In shallow water, many insects will be found if stones and logs are turned over and leaf tufts pulled apart.

In winter, insect galls or cocoons may be gathered. If these are placed in jars with cheesecloth covers tied over them, kept in a warm room, but away from radiators and all intense heat, many insects will emerge from them before spring.

WHAT TO USE

For making even a fairly large insect collection, only a small amount of equipment is required. A net and killing bottle are essential, and good work may be done with these alone. A greater variety of insects may be collected and with better results if a few more items are added to the list. Here is an outfit that will be found very satisfactory in the field.

1. A strong beating net for general sweeping and an additional light net to be used for moths and butterflies.

2. Killing bottles, several small and one or two large ones.

3. A pair of flexible forceps, 10 to 12 centimeters (about 4 to 5 inches) long, with slender prongs.

4. One or two camel's-hair brushes for picking up minute insects.

5. A few vials or small bottles containing fluid preservative.

6. Folded papers for butterflies.

7. A few small tins or boxes lined with cellucotton.

These items may be purchased from commercial supply houses such as those listed on page 71. Many items, however, may be made by the collector at nominal cost.

Nets

Nets are the most important items in the collecting kit of the entomologist. For this reason nets should be rigidly constructed and handled with care.

Construction.--Nets may easily be made at home. The necessary parts are a handle, a loop or ring to be attached to it, and a cloth bag to be hung from the loop, figs. 1 and 2. The handle should be strong and fairly light. At the net end, fig. 1_a_, a groove is cut down each side to receive the arms of the loop. The grooves are as deep as the thickness of the wire used in the loop; one groove is 3 inches long and the other 2½ inches; and each ends in a hole through the handle at right angles to the length.

The loop, fig. 1_b_, is made of steel wire, preferably three-eighths-inch piano wire, which if bent by rough usage springs back into shape and will stand a great deal of hard wear. The wire is shaped, as the figure shows, to form a loop with two straight arms, the tips of which are bent at right angles toward each other. The arms and hooks thus formed must be exactly long enough to fit along the grooves and into the holes in the handle. After the bag or net has been attached to the loop, and the wire has been fitted to the handle, the joint may either be wrapped tightly with wire, fig. 1_c_, or bound by a metal cylinder or ferrule slipped over the arms of the loop, fig. 1_d_.

The bag, about twice as long as the diameter of the loop, should be tapered at the bottom. It is made from four pieces of cloth, each cut in the shape of fig. 2_a_, and a narrow strip or band of stout muslin or light canvas, 2_b_, which is to bind the bag to the wire loop. The four pieces are sewed together to form a cone-shaped bag, and one edge of the band is sewed to the top edge of the bag.

The bag may be attached to the wire loop in either of two ways. The band may be folded over the loop and sewed so that the attachment is permanent; or it may be folded over, sewed, and then slipped on the loop before the latter is fastened to the handle. In the latter case the bag must be open along one seam just below the handle a sufficient distance to allow the band to slip on and around the loop; this vent may be closed with a string lacing after the net is on the loop, and the whole fastened to the handle. A combination of this arrangement with a ferrule binding the loop to the handle is most convenient, for it allows the bag to be removed at will and a lighter or heavier one substituted according to the needs of the collector.

_General Purpose Net._--Loop, heavy wire, 12 inches in diameter; bag, strong unbleached muslin or light duck, 20 to 24 inches long; handle, hardwood stick, 24 to 30 inches long.

_Butterfly Net._--As above but with a longer handle and a bag of good quality marquisette or fine nylon netting.

_Combination Net._--A net that includes the features and uses of the two nets described above and is a better collecting instrument may be conveniently made instead, although at slightly higher cost because of the better materials. Its loop, of 7½ gauge (three-eighths inch) piano wire, is 15 inches in diameter and allows a greater area to be covered with each sweep. The bag, of finest bolter's silk or best quality marquisette, is 24 inches long and serves equally well for the capture of delicate insects and for beating. The handle, of straight-grained hickory or ash, is 40 inches long and permits the collector to cover greater areas in sweeping. If a cheaper net is desired, one of unbleached muslin will be satisfactory for general use.

Care and Use.--All nets are easily ripped and for this reason should be kept away from barbed wire and from thorny trees, such as locust and red haw. Also, they should be kept dry. Moisture rots the fabric, making it more easily torn. Most insects caught in a net while it is wet are unfit for a collection.

Flowers, herbs, and boughs should be swept with a sidewise motion. A sidewise sweep will collect more insects than an upward or downward sweep and at the same time mutilate less. If care is taken not to damage flowers or foliage, the same patch of plants may be visited several times with profit. The contents of the bag should be removed after every few sweeps or strokes. This practice will prevent damage to the insects caused by being jostled about in the net with a large amount of debris.

Killing Bottles

The best killing agents for use in bottles are either potassium cyanide or calcium cyanide. These compounds give a concentration of deadly fumes sufficient to kill most insects in a very short time, which is desirable. Generally, two sizes of bottles are used, and in either of them one of these cyanides may give good results. Only a small supply should be purchased at a time, as they deteriorate rapidly.

Construction.--A pyrex glass test tube or strong ring-necked vial, about three-quarters inch wide and 4 to 6 inches long, makes a good cyanide bottle of the smaller size, fig. 3. Put about three-quarters inch of granular potassium cyanide or calcium cyanide flakes in the tube or vial. Cover with a tight plug of cellucotton, on top of which put one or two loose plugs. Instead of cellucotton, you may use sawdust and a plaster of Paris batter. In the latter case, cover the cyanide with one-quarter inch of sawdust and over it pour one-quarter inch of newly mixed, thick batter of plaster of Paris and water. Allow the batter to harden for a few hours; then keep the bottle tightly corked except when it is being used.

The larger cyanide bottle, fig. 3, which should be sturdy, may range in capacity from one-half pint to a quart. _In the larger bottle, the cyanide should always have the plaster of Paris covering._ The layer of sawdust and plaster should be a little thicker than that for the smaller bottle.

Care and Use.--Label all killing bottles and other containers of cyanide conspicuously with the word POISON; keep them tightly corked and away from children or adults who do not realize the extreme deadliness of the compounds. _Never test the strength of a killing bottle by taking the cork out and smelling the contents._ As an added precaution and safeguard to the collector, tape the bottom of the cyanide bottle to protect it against breakage.

The bottle should be almost entirely filled with loosely crumpled, soft paper, which should be changed whenever it gets damp. This paper will help keep the specimens from rubbing against each other inside the bottle and thereby being damaged.

Each collector should have several cyanide bottles and follow carefully these practices.

1. Transfer insects from net to bottle by holding the uncorked bottle in a fold or corner of the net and crowding one or more of the specimens into it, or "running" the open bottle up the side of the net beneath the specimen or specimens. Most insects can be maneuvered into the bottle easily and the opening temporarily closed by the thumb, or the stopper can be put on. In obstinate cases, it may be desirable to stopper the bottle through the cloth of the net until the specimen is stupefied, after which the insect will drop to the bottom of the bottle.

2. Keep small, delicate insects in a bottle by themselves. Such insects as large beetles are apt to mutilate small flies and other delicate insects in the same bottle.

3. Keep a special bottle for moths and butterflies. When these die they shed large quantities of scales, which stick to and partially spoil other insects.

4. Keep the inside of the bottle dry. Cyanide bottles "sweat"; that is, moisture both from the insects and the plaster condenses on the inside of the bottle. Moisture will mat the hair and appendages of insects and discolor the bodies. Do not crowd the bottle with large insects, especially juicy ones like grasshoppers. Change the paper frequently. Wipe out the bottle with paper or cloth, which should be carefully disposed of in such a way that it cannot poison persons or pets. Keep the killing chemical out of cuts and mouth. Wash hands with care after handling the chemical.

5. Take insects out of the bottles soon after they are dead. Cyanide fumes quickly turn many yellows to red or orange, and also make small specimens brittle so that legs and other parts break off easily.

6. Empty the insects out of the bottles before they have accumulated in a ball at the bottom. To do so will prevent damage to the smaller specimens and discoloration due to "sweating."

7. Dispose of a cyanide bottle when it will no longer kill insects quickly. Substitute a fresh bottle and you will save time in the field. Be sure to dispose of old bottles in such a way that their deadly contents are out of reach of children and pets.

Aspirators or Suckers

Small, rapidly moving insects, such as leafhoppers, diminutive beetles, and flies, may be collected by using an aspirator or sucker, figs. 4 and 5.

Construction.--An aspirator can be made from a capsule vial (available from a drugstore) or from a piece of glass tubing. A small olive bottle may be substituted for the vial.

The following items are needed for the vial aspirator, fig. 4: a vial, 1¼ inches in diameter and 3 or more inches long, a two-hole rubber stopper with openings to fit one-fourth-inch diameter glass tubing, 16 inches of one-fourth-inch diameter glass tubing, rubber tubing 24 inches long to fit over the glass tubing, a small metal file (the triangular type is best), a small piece of cheesecloth, some string, and a bunsen burner. Construct the vial aspirator according to the following directions and as shown in fig. 4.

1. Cut the glass tubing into three pieces, 3 inches, 8 inches, and 5 inches in length. To cut the tubing, score it with an edge of the metal file; then hold the tubing with both hands so that the thumb of each hand is on the side of the tubing opposite to the scored mark; break the tubing away from the body by exerting pressure with the thumbs.

2. Make a slight bend in the center of the 8-inch piece of tubing and a right angle bend in the 5-inch piece, as follows: hold one piece of glass tubing with both hands and place the center of it in the blue flame of the bunsen burner; rotate the tubing slowly. When the glass glows yellow, it begins to soften. Bend the tubing to the desired angle. Then quickly withdraw the tubing from the flame.

3. Heat one end of the 8-inch piece of glass tubing in the bunsen burner, slowly rotating the tubing so that the sharp edges melt slightly and round out; then allow the tubing to cool. Heat one end of the 3-inch tubing in the same manner. Smooth the remaining rough edges of the glass tubing by heating them slightly.

4. Insert the 8-inch and 5-inch pieces of glass tubing into the rubber stopper. The longer piece, fig. 4_c_, should project about 1½ inches into the vial. The shorter piece, fig. 4_d_, should project about three-fourths inch.

5. Over one end of the 5-inch piece of glass tubing, fig. 4_e_, tie two thicknesses of cheesecloth securely with string.

6. Over the other end of the 5-inch piece, slip one end of the rubber tubing, fig. 4_f_.

7. Into the other end of the rubber tubing slip the 3-inch piece of glass tubing, fig. 4_g_, so that the rounded end of glass is exposed.

8. Complete the assembly of the aspirator by placing the rubber stopper snugly into the vial. The vial aspirator is now ready for use.

If a piece of glass tubing 1¼ inches in diameter and 8 inches long is available, then a tube aspirator can be made, fig. 5. In making a tube aspirator, use two one-hole rubber stoppers, 5_b_. Cut the pieces of glass tubing as shown in fig. 5_c_, 5_e_, and 5_g_. Using a piece of rubber tubing, 5_f_, complete the minor details as described for the vial aspirator, not forgetting the cheesecloth, 5_e_, and assemble the parts as shown in fig. 5.

Use and Care.--To catch an insect with the aspirator shown in fig. 4 or fig. 5, put end piece, _g_, in your mouth, grasp the vial or tube, _a_, in your dexterous hand, aim the intake tube, _c_, at the insect and almost touching it; suck suddenly and hard. The air current pulls the insect in; the insect usually does not find its way into the intake tube to crawl out. The cheesecloth, _e_, prevents the insect from being sucked into your mouth.

To kill insects in the aspirator, use a small cyanide bottle, 4_i_, which is inserted in a cork, 4_h_, that has been partially bored through to receive it. This cork should be the exact size of the vial or tube for which it is intended.

To use the cyanide cork with the vial aspirator shown in fig. 4, simply exchange the corks. If the glass tube aspirator is used, plug the intake tube, 5_c_, with a tapered paper plug or a leaf, jar the insects away from the stopper at the opposite end, remove this stopper cautiously, and quickly insert in its place the cyanide cork. When the specimens are stupefied, they may be transferred to another bottle.

The cyanide corks are highly poisonous. Between times of use with an aspirator, keep each of these corks inserted tightly in a bottle or vial labeled "POISON," as in fig. 3.

Sifter

Perhaps no special collecting method results in more interesting, rare, and diverse kinds of insects than that involved in sifting rotten logs, leaf mold, and other forest and prairie ground cover. To do this type of collecting, provide yourself with the following:

1. A stout sifting sieve about 12 by 12 inches and 4 to 6 inches deep, fig. 6. The bottom may be wire screen of any desired mesh; usually 8, 10, or 12 meshes to the inch give good results.

2. A sturdy piece of white oilcloth about 18 inches or 2 feet square.

3. Collecting equipment, including an aspirator, camel's-hair brush, forceps, vials, and killing bottle.

Material such as leaf mold is placed in the sieve and this is shaken over the white oilcloth, which has been spread on a level spot on the ground. The small insects fall on the cloth and can be picked up with the aspirator or the camel's-hair brush. Many insects feign death when they fall to the oilcloth and they are difficult to detect in the bits of sifted material until they "revive" and start to move.

In late fall and winter, sifting provides one of the most profitable types of collecting; in any season, it will turn up such things as rare spiders and beetles. Sifting is most successful for finding large, active insects. For small, slow-moving forms, Berlese funnels offer a better collecting method.

Berlese Funnel

When you are wandering through woods or fields, do you realize that you are stepping on more insects than you ever see? The ground cover and soil are inhabited by a vast assemblage of little animals that are seldom seen by the casual collector. Because many of these animals are exceedingly minute, they are difficult to see and collect by ordinary methods.

Construction.--The most efficient method for collecting this fauna is by the use of Berlese funnels, named after the Italian entomologist Berlese (pronounced Bur-lazy), who first used them extensively. A Berlese funnel is a very simple apparatus, consisting of a fairly long funnel, suspended wide end up, with, a screen placed about a third of the way down the funnel; heat is applied either around the upper portion or over the top of the funnel, and a container of preservative, preferably 80 per cent ethyl alcohol, is placed at the small bottom opening. Leaf mold or other material is placed on the screen, the heat source is turned on, and soon the animals begin to leave the drying sample and migrate downward, dropping into the preservative.

Fig. 7 illustrates a funnel that has proved very satisfactory; it is 15 inches from top to bottom, and the top has a diameter of 12 inches. The bottom opening, seven-eighths inch in diameter, fits into the mouth of the bottle containing the preservative. Three angled brackets or hangers are soldered inside the funnel to provide a rest for the screen, which is made of quarter-inch or eighth-inch mesh hardware cloth; the mesh used depends upon the type of sample. A battery of several funnels in a rack, fig. 8, will allow the collector to sample several kinds of material at the same time.

If steam is used as a source of heat, the small copper lines that conduct it act as a partial support for the funnel by encircling it about halfway between the screen and the top; a piece of cloth is tied tightly over the top of the funnel to prevent the upward escape of animals. If an electric light is used for heating, it should be hung directly over the center of the funnel, no cloth should be tied over the top, and the light should have a reflector nearly as wide as the top of the funnel.

Care must be taken not to heat the sample too rapidly. Otherwise, either moisture will condense in the lower part of the funnel and trap many of the animals working their way toward the bottom, or the heat will kill many of the organisms before they have an opportunity to move out of the sample. An application of heat sufficient to dry the sample in 4 or 5 days is usually satisfactory.

The Berlese funnel is extremely useful for collecting many groups of beetles (particularly Staphylinidae), thrips, springtails, many groups of parasitic Hymenoptera, ants, mites, pseudoscorpions, millipedes, centipedes, and a wide range of other minute animals that live in soil, surface cover, logs, or bark.

Collecting Berlese Samples.--Many different habitats and micro-habitats provide good samples for the Berlese funnel. You will find that, for general collecting, various types of ground cover are excellent; for leaf mold samples, scrape off and discard the dry surface leaves and scoop up the lower, rotted layers of leaves together with an inch or two of the adjacent soil. You may encounter especially good samples where leaves have blown in along the edge of a log. In such a situation, take some of the log bark with the sample. Collect rotten log samples in large hunks and break them up just before putting them in the funnel. From either standing stumps or fallen logs in which the wood is still too hard to break up, collect the loose bark, as it is often quite productive. Frequently, if you roll a log over, you may find animal runs under it; the debris and earth under and around these runs, together with animal nests, frequently give unusual catches, such as larvae and adults of fleas and rare ticks. Especially productive are samples taken from the interior of a standing hollow tree; from the bottom of the hollow you can scoop out a foot or more of fine, rotten, woody material rich in rare insects.

Certain items placed in the funnel may produce distinctive and unusual catches. Recently deserted birds' nests will give mites and, frequently, rare beetles, flies, and their larvae; mature or overmature mushrooms and bracket fungi are often rich in beetles, thrips, and maggots; bark of living trees may produce unusual thrips, springtails, and psocids; debris from aquatic habitats and from the wet edges of ponds and tiny streams may be productive of rare aquatic and semiaquatic forms. Moss is a good source of peculiar species of springtails, thrips, and beetles; the moss should be rolled up carefully while being transported.

Handling Berlese Collections.--In the field, put samples of leaf mold or other material in tightly woven cloth bags or strong paper bags for transportation. It is convenient to have small paper bags for mushrooms, nests, and other small items, and larger bags for ground cover, moss, and the like. When collecting ground cover and similar material, put in each bag enough of a sample so that it will not shake around loosely, but do not pack it tightly. Be sure that samples do not overheat while being transported.

Samples may be collected at any season. If collected during warm weather, they should be taken to a laboratory and placed in the funnels within a day or two; otherwise, considerable loss of population occurs within the samples. If collected during cold weather, they may be kept in cold storage for a week or two with little loss of fauna.

In putting material in the funnel, lay it carefully on the screen to a depth of a few inches. Moss and sod should be placed upside down in a single layer on the screen. In the case of dense material, pile the sample chiefly around the sides of the funnel and leave an opening in the middle, as shown in fig. 7. After the funnel is loaded, place it in the rack, put the bottle of preservative under it, and apply the heat.

By substituting a different kind of collecting bottle at the bottom of the funnel, you may obtain live material for rearing. The exact changes necessary to obtain live material will depend upon your ingenuity and the type of material you desire.

Equipment for Collecting Aquatic Insects

Hundreds of different kinds of insects are aquatic and offer rich collecting possibilities. In all instances, the immature stage lives in water, but in most of them the adult stage emerges on land or flies in the air. For this reason several types of collecting are needed to obtain a good sampling of aquatic insects.

Night Collecting of Adult Insects.--Collecting at lights on warm, cloudy nights, or warm nights without moonlight, gives best results. Two simple methods are as follows:

Drive your car to a spot overlooking a stream or lake and turn on the bright lights. Into a shallow pan, such as a pie pan, pour enough alcohol to cover the bottom with one-eighth to one-fourth inch of fluid. Hold the pan directly under a headlight. If aquatic insects are on the wing, they will come to the light and eventually drop in the fluid, which traps them. With a small piece of wet cardboard, you can scrape the entire insect contents of the pan into a small bottle of alcohol, which you should then label, giving date, name of collector, and location.

Lights in signs and store windows (especially blue neon signs) near fresh water attract large numbers of aquatic insects. You may capture an insect easily by dipping an index finger in a bottle of alcohol, "scooping up" the insect rapidly on the wet surface, and then dipping it in the bottle. An aspirator also can be used with success.

Day Collecting of Adult Insects.--During the day, aquatic insects frequently rest on or under bridges, window ledges, and similar places, and show a preference for dense trees in shaded situations. They are especially numerous in those spots where the heavily leaved branches hang low over the water and form humid, protected areas in the heat of the day. Here sweeping with a stout and fairly wide-mouthed net is very effective. Aquatic insects may often be picked off stones in such places, especially early in the season.

Collecting Larvae.--Practically every stream or lake has some aquatic insect larvae which may be collected by various methods, some simple and others requiring specialized and complicated apparatus. For general collecting, the following suggestions may be of value:

1. Look under logs and stones. Search out crevices in them; some insects hide away and demand of the collector a keen and careful search.

2. Tear apart bunches of leaves, roots, and other debris that may have piled up in front of a rock or log, or that may have accumulated at the end of a root or branch dangling in the water.

3. Pick out bunches of aquatic plants and search through them carefully.

4. Sift mud, sand, or gravel taken from the bottom of a lake or stream. Remember that some insects build cases in which they hide when disturbed. It takes a practiced eye to see a motionless case. After an insect has dried out a little, it partially emerges from the case and drags it along in search of water; moving in this way, it is easy to see.

HOW TO HANDLE UNMOUNTED SPECIMENS

Soon after insects are killed they dry out, become very brittle, and are damaged easily. Small, fragile insects especially are susceptible to breakage and, when dry, break up readily into fragments. Hard-shelled insects, such as beetles, may appear to be sufficiently durable to withstand handling when dry, but even these insects have fragile legs, antennae, and other parts which snap off readily when handled dry. Newly killed material should be either mounted or put in temporary storage before it has dried out. If collected material dries out before it can be mounted or stored, it should be relaxed by special techniques so that the specimens can again be handled without danger of breakage.

Temporary Cases

If it is not convenient to mount the specimens when they are taken from the killing bottle, the moths and butterflies should be put in _papers_ and other insects in cellucotton.

Papers are simply rectangular strips of paper of convenient size folded as in fig. 9. A moth or butterfly, with its wings folded, is placed in a paper, the edges of which are then crimped over to lock it shut.

For insects other than moths or butterflies, cardboard pillboxes containing cellucotton make good temporary housing, fig. 10. A layer of cellucotton is laid in the bottom, a layer of insects placed on it, and another layer of cellucotton placed over the insects. The lid should fit fairly snugly over all. Cigar boxes and other boxes of like size also may be used in the same way.

Great care must be taken that sufficient cellucotton is put in the box to take up all moisture in the insect bodies. If the specimens are large, they should be allowed to dry moderately uncovered before being placed in cellucotton in storage containers. If insects become damp in the containers they quickly mold or rot. The containers should be wood or cardboard boxes, for they will not sweat, as will a metal box. The insects should be packed tightly enough to prevent their rolling around and breaking.

Relaxing Boxes and Jars

At any desired time the dry specimens may be relaxed and mounted. A relaxing box or jar is easily made. In the bottom of a wide-mouthed jar with a screw-on lid, put an inch or two of clean sand; saturate the sand with water containing a small amount of phenol (carbolic acid) and place over it a piece of cork, cardboard, or wood cut to fit the jar. Place the dry specimens on the cork or other material, and cover the jar tightly with the screw-on lid. The lid must be practically airtight. In a day or two the specimens will be soft and pliable enough for pinning or spreading, the next steps toward permanent arrangement of the collection.

The relaxer will sweat if kept in too hot a room and will spoil the specimens. Also, the insects will be spoiled if left in the relaxer too long. The correct length of time varies with each relaxer and can be learned only by experience.

HOW TO MOUNT AND PRESERVE SPECIMENS

Most adult insects in collections are mounted on pins. Most medium-sized to large insects, such as grasshoppers, butterflies, moths, flies, bees, and many beetles should be pinned directly through the body from top to bottom. Many small insects, such as leafhoppers, plant bugs, small beetles, and the like, should be glued on card points. Immature insects and the adults of some groups are best preserved in fluid.

Preservation by Pinning

Hard-bodied insects, such as beetles, flies, and wasps, are preserved as dry specimens on pins better than in fluid. The pinned specimens are more convenient to study and they retain their natural coloring better. Flies and butterflies are covered with hairs or scales that clot or break off if the specimens are preserved in fluid, and for this reason they should be pinned.

Common household pins are too thick and short for pinning insects. Longer, slender pins called insect pins are necessary and may be purchased from various supply houses. They should be of spring steel; a brass pin will corrode and be destroyed by acids in the insect's body. The pins are available in numbered sizes, of which 1, 2, 3, and 4 will be found of most general use, and sizes 0 and 00 of advantage in special cases.

Medium to Large Insects.--Medium to large hard-shelled insects such as moths, beetles, flies, bees, and wasps, should be pinned vertically through the body, fig. 11_a_. It is essential that the pin pass through a fairly solid part of the body, and, to insure this, the following standard procedures should be adopted:

1. Bees, wasps, flies.--Pin through thorax between bases of front wings slightly to right of middle line, fig. 11_b_.

2. Stink bugs.--Pin just to right of middle line of the scutellum or large triangle between the bases of the front wings, fig. 11_c_.

3. Grasshoppers.--Pin through back part of prothorax (the saddle behind the head) just to right of middle line, fig. 11_d_.

4. Beetles.--Pin near front margin of right wing cover near middle line, fig. 11_e_.

5. Moths, butterflies, dragonflies, damselflies.--Pin through the center of the thorax between the bases of the front wings, fig. 12.

The insect should be pushed about three-quarters of the distance up the pin, but not so close to the top that no room is left for easy handling of the pin with the fingers. It is well to have all insects the same distance from the top of the pin. To insure a uniform distance, the collector should use a pinning block. This is a small piece of wood or metal usually in the form shown in fig. 13, into the top of which are drilled holes slightly larger than the pin diameters. Such a block may be fashioned of wood with holes made by small nails and covered with a cardboard rectangle through which have been stabbed holes the exact size of those in the wood. The depths of the holes in the block should be three-eighths inch, three-quarters inch, and 1-1/8 inches, respectively. To use the block, pin the insect and insert the pin into whichever hole allows the specimen to be pushed up the pin and still leave room, allowing for the thickness of the insect's body, for handling at the top.

Tiny Insects.--Very small insects should be mounted on card points or on minuten pins. Regular pins would break too many of the insects' body parts.

Card points are small triangles of cardboard or plastic pinned through one of the sides and crimped over at the opposite apex; a spot of strong glue is put on the angled tip, and the right side of the insect is pressed against the glued surface, fig. 14. The slant of the crimp depends on the angle of the insect's side; the desired product is the insect mounted with its top surface horizontal and its head forward; legs, wings, and antennae should be in view and as little of the body as possible hidden by the glue or card point. Very little glue should be used; a small amount holds well and gives a better specimen for study than a large amount. The points may be cut uniformly with a hand punch, and they should be about three-eighths inch long. Good material for making these points is 2-ply Bristol board.

Minuten pins are short, extremely delicate steel pins, fig. 14_d_. One of these is thrust through the body of the insect and into a small piece of cork, pith, or similar substance, which is in turn pinned in the regular way a card point is. This method is especially desirable for tiny moths.

Insects Hard to Pin.--Wasps, lacewings, damselflies, and similar insects have an abdomen that sags readily when the specimen is killed and pinned. This unwanted drooping can be prevented in three simple ways. (1) Stick the pinned insect on a vertical surface of a block so that the body by its own weight dries in normal position. (2) Pin the insect on a horizontal surface and run a stiff paper on the pin beneath the body in such a way as to support it in a natural position until the insect dries. (3) Brace the abdomen by crossing two pins beneath it and thrusting them into the block, allowing the specimen to dry in the angle of the cross.

Crane flies are unwieldy and so are best pinned on a double card point mount, fig. 15. The legs should be directed away from the pin to avoid breakage in handling.

Spreading Board for Moths and Butterflies

Moths and butterflies should have their wings spread before being put into the collection. To do this well, it is necessary to have spreading boards that are accurately made but that are not necessarily complicated or expensive.

Construction.--A convenient board for medium-sized insects can be made at home of the following materials:

1.--A hardwood base, 4 x 12 x ¼ inch.
2.--Two hardwood end pieces, 4 x ¾ x ½ inch.
3.--Two softwood top pieces, 1-7/8 x 12 x ½ inch, with the top surface
planed at an angle, so that the thickness at one edge is ½
inch and at the other 3/8 inch.
4.--Two flat cork pieces 1 x 11 x ^3/_1_6 inch.

Nail the top pieces to the ends so that the slanting surfaces of the tops are uppermost and the narrower edges parallel and one-quarter inch apart, fig. 16. Glue one strip of cork beneath the top pieces, covering the opening between and fitting snugly at each end. Glue the other cork piece flat to the upper side of the base, lengthwise along the middle, and extending to within one-half inch of each end. Finally, nail the base across the bottoms of the end pieces, so that the two corks face each other.

Use.--Before spreading the specimen, relax it as described under "Relaxing Boxes and Jars." Then pin it, keeping in mind fig. 12 and the directions given under "Preservation by Pinning." Thrust the pin, with the insect on it, through the upper cork of the board and into the cork on the base. Insert the insect body in the groove so that the wing bases are level with the near edge of each top piece. Hold the wings at the top level by two narrow strips of paper and pull them forward until the hind margin of the front wing is at right angles to the body axis, and the front margin of the hind wing is just under the front wing, fig. 16. Pin the wings temporarily in this position by inserting a pin, size 0 or 00, near the front margin at the base of each wing. When the wings on both sides of the insect are thus adjusted, lay strong pieces of paper over them and pin them down securely with large pins inserted close to the wings but not through them. Here you may use large common pins, but still better are the large-headed dressmaker's pins about 1¼ inches long. Finally, remove the original adjusting pins and put the specimen in a dry, pest-proof container for 2 or 3 weeks. It will then have set sufficiently to be removed from the board.

For good results, spreading boards with grooves of various widths are necessary; a specimen should be spread on a board with a groove that fits the body. The width of the top pieces should vary to accommodate different wingspreads. The slope of the top pieces should be about as described.

Preservation in Fluid

Caterpillars and other immature stages of insects should be preserved in 80 per cent grain alcohol. Caterpillars, grubs, and maggots should first be heated 5 to 10 minutes in water just at the boiling point. This treatment sterilizes the specimens and prevents their discoloration by bacteria in the digestive system.

Many soft-bodied adult insects, including bristletails, springtails, stoneflies, and caddisflies, also should be preserved in fluid. If pinned, they shrivel to such an extent that few identifying characters can be seen. The preserving fluid in the vials in which insects have been placed should be changed at the end of the first day or two.

Some hard-shelled insects may be preserved in fluid. Ants and beetles may be thus treated temporarily and later pinned and dried.

HOW TO LABEL THE SPECIMENS

To be useful to the entomologist and others interested in the scientific relations of insects, as well as to furnish the collector with a complete record of his hours in the field and make more valuable the work he has already accomplished, the specimens should be labeled. The important information to be put on the label of each specimen is the locality and date of capture, but greater scientific value will be attached to the specimen by adding the name of the collector and the host on which the insect was found, or the particular habitat in which the insect was caught.

Labels should be made of a good grade of white paper stiff enough to stay flat when pierced and pushed up the pins. A very satisfactory high quality paper is available under the name "substance 36 ledger." The labels may be printed by hand with a crow-quill pen and black India ink, or they may be purchased completely or partially printed from a biological supply house. They should be as small as possible and of nearly uniform size. They should be pushed up the pins, fig. 14, not too near the specimens, and they should project from the pins in the same direction as the specimens. To keep the labels small, yet to include all desirable information, it is often well to record the locality, collection date, and collector on one label, and the host plant or other pertinent information on a second label, fig. 14.

When the specimen is identified, its name should be recorded on still another label, which should be kept low on the pin. Sample identification labels are illustrated by the bottom labels in fig. 14.

HOUSING THE COLLECTION PERMANENTLY

After the specimens have been pinned and labeled, they should be housed in boxes or cases having a soft bottom or inner layer that will allow easy pinning. Such housing not only insures the safety of the collection but makes for easily handled units once the specimens have been named.

Insect Boxes

Several satisfactory types of boxes for housing insect specimens may be bought from commercial supply companies. These are usually much better than boxes of home construction, being more nearly dustproof and pestproof. Homemade boxes, however, are quite practical for the beginning collector, due to their ease of construction and extremely low cost. Cigar boxes 2 inches deep or more make ideal insect boxes if a layer of cork or balsa wood or two layers of soft, corrugated cardboard are glued in the bottom. Other wooden or cardboard boxes may be provided with such a bottom pinning surface and used for storing specimens. Boxes of this type, however, afford the specimens no protection against pests, and great care must be exercised in keeping the boxes fumigated.

Manufactured boxes, cabinets, and cases may be selected from catalogs that various scientific supply firms send free upon application.

Precaution Against Pests

Certain insects, such as flour beetles and carpet beetles, feed upon dried insects, and unless precautions are taken these may entirely destroy a collection. To guard against them, various chemical repellents may be placed in the boxes containing specimens. Naphthalene, of which ordinary mothballs are composed, is one of the best repellents. A few mothballs may be put in a cloth bag pinned securely in one corner of the box, or the heads of common pins may be inserted into naphthalene mothballs, and the points stuck in the corners of the box, fig. 17.

Naphthalene is chiefly repellent in action; its odor keeps out pests, but, if they are already in the specimen boxes, naphthalene will usually not kill these pests, and some other substance must be used.

Paradichlorobenzene, called PDB, is a good fumigant to use on pests in the collection. It should be used in a nearly airtight container, such as a tight trunk, bin, or case, at the rate of 1 pound of PDB to 25 cubic feet of space. The boxes of specimens, with lids open or removed, should be placed in the container, the fumigant scattered or spread on a piece of cloth or paper above them, and the container sealed for about a week.

THE INSECT WORLD

When the insects have been collected, mounted or preserved, and labeled, the next step is to identify or name them. This is no easy task, because there are so many different kinds of insects. In the whole world there are well over 1 million different kinds and in Illinois alone probably 20,000 different kinds.