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.
[Illustration: 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.]
[Illustration: 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.
[Illustration: 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, 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.