214 



THE COCKROACH 



in modern times, but without the perfect diaphaneity of the 

 palaeozoic species ; in some the anal veins fall in true palceo- 

 blattarian fashion on the inner margin, while in others which 

 cannot be dissociated generically from them, the anal veins are 

 disposed as in modern types. But in all there is a loss of one 

 of the principal veins, or rather an amalgamation of two or 

 more a characteristic of more fundamental character. As a 

 general rule, moreover, to which w r e shall again advert, the 

 mass of the species are of small size, in very striking contrast 

 to the older types. 



To return now to the Triassic deposits of Colorado, we recog- 

 nize here an assemblage of forms of a strictly intermediate 

 character. Here are PalcBoblattarice and Neoblattarice, side by 

 side. The larger proportion are Palceoblattarice, but all of them 

 are specifically, and most of them generically, distinct from 

 palaeozoic species, and all rank high among Blattinarice; still 

 further, the species are all of moderate size, their general 

 average being but little above that of mesozoic Cockroaches, 



Fig. 122. NeorthroUattina Lakesii Scudd. X 5. Trias, Colorado. 



and only a little more than half that of palaeozoic types. The 

 Neoblattarice of this Triassic deposit are still smaller, being 

 actually smaller than the average mesozoic Cockroach, and one 

 or two of them, of the genus Neortlirollattina (see figure of 

 N. Lakesii), have marked affinity to one of the genera of 

 PalceoblattarifB (Poroblattina) peculiar to the same beds, differ- 

 ing mainly in the union or separation of the mediastinal 

 and scapular veins ; while others, as Scutmoblattina, have a 



