THE suction bottle, or aspirator, is a convenient device for collecting small insects from the beating net or beating cloth or directly from under stones, bark, and such. Its construction is rather simple. For the type illustrated in figure 3, A, the following materials are needed : A glass vial 1 to 1 1/2 inches in diameter and about 4 1/2 inches long; a rubber stopper with two holes in it; two pieces of metal or plastic tubing, one about 1/4 inch in diameter and to inches long, the other slightly larger and 4 or 5 inches long; a piece of rubber tubing about 3 feet long and big enough to slip onto the larger of the metal or plastic tubes; and 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 bolting cloth should be fastened over the end of the larger metal tube to keep the insects from being sucked into the mouth. If wire screen is used it may be soldered to the end of the tube. Glass tubing may be used, but it has the disadvantage of breaking easily. The length and size of the tubing and the degree of the bends may be adapted to the user's convenience.

When the aspirator is assembled, place the end of the rubber tubing 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, small flies, tiny beetles, and other minute insects normally killed in liquid is illustrated in figure 3, C. 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.

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 substituting for the shorter tube, to which the rubber tubing is attached, the attachment illustrated in figure 3, E. This piece of equipment makes use of an air current to create a partial vacuum; 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 disagreeable odors.

Many insects spend all or part of their lives in ground litter and leaf-mold. They cannot be captured by ordinary collecting methods. Because they are too active to be caught by hand or 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 into 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 collecting in winter.

THE COLLECTOR who wishes to get large numbers of the small insects that are usually found in ground litter will find it advantageous 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 leaf-mold 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.

Collecting around 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. The use of light traps as a means of obtaining insects for the collection is not recommended because specimens are too frequently damaged. Insects for the collection should be selected and captured by attending the light 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; the lower edge is turned up to form a trough into which some of the insects will fall. The specimens are collected as they come to the sheet. Many insects may also be collected around street lights and lighted store windows.

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 or fermenting fruit juices, and daub it on tree trunks along a route that can be conveniently visited with a lantern or flashlight. 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.

Insects that are attracted to 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 frequently desirable to set these traps under loose boards or stones lying on the ground.

AN ASSORTMENT of tweezers and brushes should be available as an aid in collecting and handling the specimens after they are dead. Such equipment may be purchased at small cost from most biological supply houses. 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 preservative, touch the specimen with the brush, and you can transfer it safely to the collecting vial.

REARING is one of the best methods of obtaining good specimens. It has the added advantage of permitting observations on the life history of the species and enables the collector to get examples of the various immature stages.

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 or sand 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 emerge 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 excellent for this type of rearing.

Adult moths, butterflies, beetles, and many other insects may be obtained by collecting chrysalids or 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.