FIELD BOOK OF INSECTS. 



Should insects get dry and stiff before they are spread, 

 they must be relaxed. This is done by putting them in a 

 covered jar or tin box containing water or moist blotting 

 paper. A few drops of carbolic acid added to the water 

 will prevent mold. Twenty-four hours will usually be 

 sufficient to relax even the driest, but more time may 

 sometimes be necessary. If the insect has neither scales 

 nor hairs, it can be quickly relaxed by immersing it in 

 warm water. 



It will be noticed that both of the setting boards illus- 

 trated here give the wings a slight upward tilt. If they 

 keep this position, it will not be objectionable, but they 

 are not likely to do so, since the weight of the wings will 

 probably drop them at least to the horizontal. Large 

 insects dry more slowly than small ones and it will prob- 

 ably be necessary to allow them to remain on the boards 

 for about two weeks. They should certainly remain until 

 thoroughly dried. No further preservation is then 

 necessary, as a rule, for the fairly hard-bodied, adult 

 insects. Some tropical grasshoppers have large abdomens 

 full of fat and decomposing food. These should first be 

 opened by an incision along the belly, the viscera taken 

 out, and the abdomen stuffed with cotton. 



Broken insects may be repaired by the use of shellac 



or thin glue. 



Caterpillars may be prepared in the following way: 

 Make a circular incision at the hind end, cutting the in- 

 testine loose from the outer body wall. Then, laying the 

 caterpillar on a piece of clean blotting paper, squeeze the 

 viscera through this opening by gently rolling the cater- 

 pillar with a lead pencil, beginning near the hind end and 

 gradually working toward the front. After the viscera 

 have been gotten rid of, for the most part, insert a straw 

 and fasten the first segment of the larva to the end of the 

 straw by means of a fine needle. Draw the hind segment 

 up the straw until the larva is natural length and fasten it 

 in the same manner. Then, inflate the larva by gently 

 blowing through the straw. Since the front end of the 

 straw may get plugged up, it is well to make a small hole 

 in the side of the straw before it is inserted. This hole 

 had best come about midway between the larva's head and 



22 



