DISTRIBUTION 



387 



FIG. 297. 



number and variety, still restricted, however, to the more 



generalized orders. The dominance of cockroaches in the 



Carboniferous is especially noteworthy, no less than 200 Palaeo- 



zoic species being known from Eu- 



rope and North America. These 



ancient roaches (Fig. 297) differed 



from their modern descendants in 



the similarity of the two pairs of 



wings, which were alike in form, 



size, transparency and general neu- 



ration, with six principal nervures 



in each wing; while in recent cock- 



roaches the front wings have be- 



come tegmina, with certain of the 



veins always blended together, 



though the hind wings have retained 



their primitive characteristics with a 



few modifications, such as the ex- 



pansion of the anal area. Car- 



boniferous cockroaches furthermore 



exhibit OvipOSitOrS. Straight, Slender, 



and half as long again as the abdo- 

 men organs which do not exist in 

 recent species. 



Lithomantis (Fig. 298), a remarkable form from Scotland. 

 possessed in addition to its four large neuropteroid wings, 

 a pair of prothoracic wing-like appendages which, provided 

 they may be regarded as homologous with wings, represent 

 a third pair, either atrophied or undeveloped a condition 

 which is never found today, unless the patagia of Lepidoptera 

 represent wings, which is unlikely. 



From the rich deposits of Commentry, Brongniart has des- 

 cribed several forms of striking interest. Dictyoneura is a Car- 

 boniferous genus with neuropteroid wings and an orthopteroid 

 body, having, in common with several contemporary genera, 

 strong isopteran affinities. Corydaloides scuddcri, a phasmid, 



Etoblattina masona, a Car- 

 boniferous cockroach from 



Illinois. Twice natural size. 

 ScuDDER in Mia11 and 



