ORDER ORTHOPTERA 55 



the hind legs much enlarged and adapted for leaping. The 

 group is conveniently divided on the basis of their move- 

 ments into the rinniing or walking and the jumping divisions. 

 Cockroaches. — Of these groups the cockroaches, family 

 BJaiiukr, may he considered as about the most ])rimiti\e 

 representatives for the winged insects, the P>phemeri(Ue, 

 often placed as the lowest order, having been specialized 

 in the direction of aquatic life. This position is supj^orted 

 by the primitive structiu-e of the mouth, by the venation of 

 the wings, and also by the fact that they are to be found in 

 strata of the early Paleozoic era, the earliest to appear of the 

 winged insects whose structure agrees quite closely with 

 that of present-day cockroaches. No other winged insects 



Fig. 21. — Ischnoptera fietm.sylvanica. After Lugger 



have been found in any numbers in as early geologic forma- 

 tions. Cockroaches of the present t'me seem to be persistent 

 forms that have preserved ancestral characters. Their 

 life history is interesting on this account. 



One species of cockroach {Ischnoptera pennsyJminca) is 

 fairly common in woods under bark of dead timber and 

 sometimes in houses. The females are often found with the 

 egg-capsules protruding from the body. It is abundant 

 all over the I'nited States and is really an outdoor native 

 species. They ha\e well-developed wings, and often fly 

 into houses and are found in stumps, under logs, etc., during 

 daytime, and make migrations during the night, or in the 



