THE TRUE BUGS 



121 



The squash-bug and its relatives form another large family 

 (Coreidae] of some two hundred species, of which the common 

 squash-bug (Anasa tristis], which we have already considered 

 (p. 50), is the best-known example. In the middle and southern 

 states there are several nearly related species 

 which have the hind tibia flattened and ex- 

 panded somewhat like a leaf, and are known 

 as leaf-footed plant-bugs. The box-elder bug 

 (Leptocoris trivittatus] is a common species 

 throughout the Mississippi Valley and Great 

 Plains, where it is a serious enemy of the 

 box elder, which is planted largely for shade. 

 It is blackish, with three bright red lines on the 

 prothorax, and with fore-wings having edges 

 and veins of a dingy red. 



FIG. 164. Box-elder 



bug (Leptocoris trivit- 



tatus}. (Twice natural 



size) 



(After Kellogg) 



SUBORDER PARASITA 



As their name indicates, the members of 

 this suborder are parasites upon man and other 

 mammals, being commonly known as lice. They may well be called 

 the true lice, or sucking lice, to distinguish them from the bird-lice 

 (Mallopkaga), plant- 

 lice (Aphididae), and 

 other insects com- 

 monly called lice. 

 They are small, soft- 

 bodied, wingless in- 

 sects, with a stout, 

 unsegmented beak, 

 either without eyes or 

 with only simple eyes, 

 and the tarsi bear but 

 a single claw, all of 

 these characters indi- 

 cating a degenerate 

 group. The head-louse infests the hair of man, and the body- 

 louse, or grayback, as soldiers term it, lives in and lays its eggs in 

 the seams of clothing. - The general appearance, greatly enlarged, 



FIG. 165. Sucking lice affecting man. (Greatly 

 enlarged) 



a, crab-louse (Pthirius ingninalis Leach) ; Z>, head-louse 



(Pediculus capitis De G.). (a, after Denny ; t>, after Packard ; 



from Osborn, United States Department of Agriculture) 



