ROSS: HOW TO COLLECT AND PRESERVE INSECTS 



41 



Some of the outdoor species become very abundant on drying 

 corn leaves during autumn and may breed in immense numbers. 

 They do little harm, feeding chiefly \ \ 

 on fungus strands. ns^ 



V 



Fig. 39. — Corrodentia. Psocus striatus, 

 a common bark louse found on many 

 trees. Actual length 0.2 inch. 



JJ 



Coleoptera These are insects with two pairs of wings, 



Beetles, the second pair delicate and folded under the 



Weevils first pair, which are hard and thickened and 



folded back over the body, touching each 



other at the edges to form a hard shell, as shown in Copris 



minutus (Drury), fig. 40. The upper wings are not used for 



locomotive purposes, but form part of the body armor and are 



Fig. 40.— Cole- 

 optera. Copris mi- 

 nutus, one of the 

 scarab beetles. 

 Note one of the 

 elytra upraised 

 and the method 

 of folding the 

 hind pair of 

 wings under 

 them. Actual 

 length 0.4 inch. 



called elytra. In most beetles they cover the entire posterior part 

 of the body ; in many others they are abbreviated and cover only 

 part of the abdomen. The immature stages of the beetles are 

 wormlike or grublike and 

 have a great variety of food 

 habits. Some of them de- 

 foliate plants, others attack 

 roots, and still others feed 

 on other insects. 



Fig. 41. — Coleoptera. Curcu- 

 lio caryae, one of the hickory 

 weevils. Note the beak. In this 

 group it is exceptionally long. 

 In most of the Illinois weevils, 

 the beak is shorter and stouter. 

 Female, a and 6; male head, c. 

 Actual length 0.4 inch. 



