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.
Fig. 4.—Vial type of aspirator or sucker. End g is placed in the mouth; c is used to pick up the insects. Shown also is a cyanide cork, h-i, which is used to kill insects in the aspirator.
Fig. 5.—Tubing type of aspirator. Parts for this aspirator should be compared with equivalent parts for the aspirator shown in [fig. 4]. Noted especially should be the position of the glass tube, c, and the length of the rubber tube, f.
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.
Fig. 6.—Sifter with hand grips. Debris containing insects is sifted over a piece of white oilcloth. The sifter, not more than half full, is shaken gently at first and then violently. Finally the debris that cannot be shaken through the sifter is emptied on the oilcloth, and specimens too large to go through the mesh of the sifter are captured. Patience is required to get the best results with the sifter, which provides one of the best methods for winter collecting.
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, 5c, 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].