MKSOZOIC COCKROACHES. 473 



they should be separated generically; but their close resemblance in neuration, which is 

 at the same time in most parts of the wing - less dense, leads me to suspect that they may 

 really be hind wings of species of Pterinoblattina of a more elongate form than any yet 

 known (the species vary considerably in this direction), and that for this reason it may 

 be well at least for the present to place them here, doubtfully. The wing referred to 

 the present species is between three and four times longer than broad, subequal, tapering 

 to a somewhat pointed but rounded tip, the latter on the middle line. The scapular 

 branches succeed the mediastinal, in a common, equal, narrow band, which follows the 

 costal margin to just below the tip; the anal area, in a broader, apically tapering band, 

 witli much more distant nervules, reaches to the middle of the outer half of the wing; 

 while the long and sinuous, basally distant, apically crowded and forked median veins 

 occupy the intervening space. 



Length of fragment, 21.5 mm; probable length of wing, 2d mm. ; breadth, G.G mm. 

 It comes from the lower Purbecks of Durdlestone Bay, England. 



Pterinoblattina? Binneyi. 



[Without name] Westw., Quart. Journ. Geol. Soc. Loud., x, 390, 396, PI. 18, tig. 42. 



This wing has the same general form and proportions as P. Sipylus excepting that 

 the extreme tip of the wing is next the lower margin and not on the middle line, but the 

 scapular area still holds the same relation to it as in that species, bending downwards 

 and embracing it. The anal area is more uniformly tapering and does not extend quite 

 so far, giving ampler space for the median nervules, which appear (they are not so ex- 

 actly delineated) to have the same character as in P. Sipylus. It is a considerably 

 smaller species. 



Length of fragment, 10.5 mm; probable length of wing, 12 mm.; breadth, 3.75 mm. 

 Lower Purbecks of Durdlestone Bay, England. Named for Mr. E. W. Binney. 



BLATTIDIUM Westwood (restr.). 



Blattidium Westwood, Quart. Journ. Geol. Soc. Loud., x, 391, 396, without descrip- 

 tion; Scudd., Proc. Acad. Nat. Sc. Philad., 1885, 11 1-112. 

 Westwood designated four of the considerable number of mesozoic cockroaches which 

 he figured in 1850 by the name of Blattidium. One of these, B. Molossus, was after- 

 wards taken by Giebel as the type of his Nethania, based on an entirely wrong concep- 

 tion of the neuration, and which, as we have seen above, falls properly into his genus 

 Elisama. A second species, B. Achelous, is probably neuropteroid, and will not be con- 

 sidered here. The other two form a second very peculiar type of cockroaches, quite as 

 strange as Pterinoblattina, though very different from that, both from their long, slender 

 and parallel-sided form, and from the union of the externomedian and scapular veins for 

 nearly half their length. The mediastinal vein terminates not far from the middle of 

 the wing, and sends out a multitude of crowded offshoots to the margin. The united 



