MKSOZOIC COCKROACHES. 4G3 



compound. The externomedian is arcuate at base, first forking opposite the tip of the 

 anal furrow, shortly after which the forking - branches become completely longitudinal 

 and occupy apically a very narrow portion of the extreme apex. The internomedian 

 first forks back of the fragment and with its branches has a decidedly arcuate sweep, all 

 the veins in the apical half of the wing being almost completely longitudinal, and im- 

 pinging at subequal distances along the whole inner margin beyond the anal furrow. 

 In this particular it rather resembles liithma, but this is brought about by the single fact 

 that the innermost branch, just opposite and close to the tip of the anal furrow, has a 

 forked branch which sends three shoots to the margin close beside it, but for which, all 

 the terminal branches would reach beyond the middle of the wing. The anal furrow 

 is only seen near the end. where it is straight and oblique and probably strikes the mar- 

 gin before the end of the basal third of the wing. 



Length of fragment, 18 mm.; probable length of wing, 22.5 mm.; breadth, 8.3 mm. 

 It comes from the Lias of Dobbertin, Germany. 



Mesoblattina antiqua. 



[Without name] TVestw., Quart. Journ. Geol. Soc. Lond., x, 395, PI. 17, fig. 10. 

 liithma antiqua Gieb., Ins. Yorw. 319. 



Blattidium antiquum Ileer, Viertelj. naturf. Gesellsch. Zurich, ix, 290. 

 Mesoblattina antiqua Scudd., Proc. Acad. Nat. Sc. Philad., 1885, 115. 



This species is peculiar for its remarkable form, the costal margin being nearly straight 

 and the inner and apical margin strongly curved, throwing the apex of the Wing far 

 above the middle; in this respect no species but M. Mathildae resembles it; but the form 

 is exaggerated in Westwood's figure from the fact that the base is wanting, which, if 

 supplied, would probably make the wing about two and one-half times longer than broad, 

 instead of the extreme brevity of only twice as long, as the fragment is. Marginal field 

 and anal area are altogether wanting in the preserved portion, although it is probable 

 that the anal furrow is shown; in which case the latter must have had a sinuous course 

 from a strong outward curve at tip, and have terminated considerabty beyond the basal 

 third of the wing. The mediastino-scapular vein is very sharply sinuous, terminating at 

 the elevated tip of the wing and making the costal area twice as broad (half the breadth 

 of the wing) in the middle of the outer, as in the middle of the inner half of the wing - , 

 its branches very longitudinally oblique, the generally simple basal ones more so than 

 the outer ones. The externomedian is much more important than the internomedian vein, 

 occupying more than twice the area, and as much marginal space, its forking branches 

 uniformly and rather strongly arcuate throughout, apically parallel to the outer branches 

 of the costal area. 



Length of the fragment, 7.25 mm.; probable length of wing, 9 mm.; its breadth, 3.5 

 mm. It comes from the Lower Purbecks of Durdlestone Bay, England. It will pos- 

 sibly be found to belong in Elisama. 



MEMOIRS BOSTOS SOC. NAT. IITsr., VOL. HI. t 



