ELEMENTARY STTDIKS IX INSECT LIFE 



exclusively under the bark of tree-, as a certain beetle; 1 

 or parasitic in tbe skin of certain animals, as the spider- 

 like fly; 2 or live in dark caves, as the small ground 

 beetle; 3 or lead subterranean lives, as the small beetle 4 

 which dwells in ants' nests. 



FIG. 27. Section through eye of fly 

 vomitoria), showing arrangement of nerve-end- 

 ings of simple eyes beneath cornea (c). (After 

 Hickson.) 



At certain stages in growth and 

 development some insects find no 

 use for eyes. The larva 1 of flies, 

 commonly called maggots, being 

 placed by their parents upon 

 proper food, into which they fre- 

 quently burrow, need no eyes. 

 The same is true of Hymenop- 

 trrons larva\ the offspring of bees 

 and wasps. The larva 1 of bec- 



Fiu. 28. One of the simple eyes 



ties with like habits are also (ommatidiwiO from the compound 



eye of the fly (Musca vomitoria). 



eyeleSS. Bllt all these forms c, cornea ; pc, pseudocone ; pg'< pig- 



, , ,, , . ments surrounding and separating 



When they paSS from tlllS Stage each eye from theother ; R, central 



,-] -\ -\, r axis of the nerve-ending semidia- 



to the adult form possess eyes. grammatic . (Ater 



l Ptilium. -Nycteribia. 3 Anophthalmus 



