CO LEO P TERA . 595 



to tropical regions, and, except in the far South, only a single 

 species occurs in this country. This species is the Northern 

 Brenthid, Eupsalis minuta (Eu'psa-lis mi-nu'ta), which is 

 represented by Figure 726. In the female the head is pro- 

 longed into a slender snout ; but in the male 

 the snout is broad and flat, and is armed with a 

 pair of powerful jaws. These are weapons of 

 offence, for the males fight desperately for their 

 mates ; and, too, the males are generally larger 

 than the females an unusual occurrence among Fic - 726. 

 insects. It is interesting, as has been pointed out by Mr. 

 A. R. Wallace in his " Malay Archipelago," "as bearing on 

 the question of sexual selection, that in this case, as in the 

 stag-beetles, where the males fight together, they should 

 be not only better armed, but also much larger than the 

 females." 



The Northern Brenthid is found upon oak-trees, in the 

 solid wood of which the larvae bore, and is widely distributed 

 over the United States and Canada. 



One species of Brenthus is found in Southern Florida 

 and two in Lower California. In this genus the snout is 

 slender in both sexes. 



The only other representative of this family that occurs 

 on this continent north of Mexico is the Sweet Potato Root- 

 borer, Cylas formica rius (Cy'las for-mi-ca'ri-us), of Louisiana 

 and Florida. This beetle is somewhat ant-like in form ; the 

 color of the elytra, head, and snout is bluish black, that of 

 the prothorax reddish brown. 



Family CALANDRID^; (Ca-lan'dri-dae). 

 The Bill-bugs. 



To this family belong some of our most common snout- 

 beetles. Here the lateral edge of the metathorax and of 

 the abdomen fits into a groove in the wing-cover, and the 

 surface of the wing-cover in this groove has a pearly lustre ; 



