GEOIvOGY OF IvA SALIvE COUNTY. 



89 



DIPTERA OR TWO-WINGED INSECTS. 



These are mostly small and inconspicuous crea- 

 tures, but many of them very important, being- in the 

 larval staofe very destructive of veg^etation, as the 

 Hessiarn fly — cecidomijia destructor and c tritici or 

 American wheat fly; injurious to oats, barley and rye, 

 as well as wheat. 



The Horseflies — Tabanidse contains several blood- 

 thirsty species. The Asilici live on other insects; the 

 Bomyliaria or Bee flies; the ^stridse or Bot flies of 

 several genera and more than twenty species, attack- 

 ing horse, sheep and ox; the Muscid^ or Flies proper. 

 The house fly and its allies and many others are 

 included in the Dipteral, as also the Pulicids or fleas. 



The Coleoptera or Beetles, commonly called bugs, 

 are at once known by their having their wings covered 

 by a hard, usually lustrous cover, and look as if 

 they were covered with horn. These covers are 

 called elytra. Among the most common are the bril- 

 liantly colored Calasoma scrutator, a beautiful green 

 and the no less handsome C. calidum, black with six 

 rows of bright red. sunken spots on the back. They 

 belong to the Cincindelidse or Tiger Beetle family, all 

 of which eat other insects. 



The Dycticeds or Water Beetles, Gyrinedae and 

 Hydrophilida^ are all inhabitants of the water, the 

 last flj'ing by night; the Silphidae or Carrion beetles 

 have the curious habit of burying dead mice, snakes, 

 etc., and la\^ing their eggs in them; Staph^denidae live 

 on decaying matter, animal or vegetable; Dermestedoe 

 in its larval state eats the dried skins and bodies of 

 animals, and is verv destructive to zoologfical collec- 

 tions; Ivucanidae are large, stout and handsome beetles, 

 sometimes called Horn bug-s from the appearance 

 of their upper jaws; Scaraboeidae have their antenna 



