1885.] NATURAL SCIENCES OF PHILADELPHIA. 39 



of the wing before curving upward again to terminate above the 

 apex. The externomedian vein is arcuate and terminates on the 

 lower margin not far from the tip, and has only three or four 

 superior longitudinal branches. The anal furrow is strongly 

 arcuate. The anal veins are nearly parallel to the inner margin, 

 but impinge upon it near the anal furrow. 



Poroblattina arcuata, nov. sp. 



The costal border is considerably convex. The scapular vein 

 is unusually arcuate and has a large number of mostly simple 

 oblique branches. The externomedian and internomedian veins, 

 on the contrary, have few and distant branches, and the former 

 is also strongly arcuate. The whole surface of the wing is broken 

 by closely crowded cross-veins, which are more transverse to the 

 whole wing than to the interspaces. A single, rather imperfect 

 specimen is known, indicating a species with a wing about 10 mm. 

 long; the width is 4 mm., and apparently the wing was well 

 rounded and much shorter in proportion to its breadth than in 

 the next species. 



Triassic beds near Fairplay, Colorado. 



Poroblattina lakesii, nov. sp. 



The costal border is nearly straight and the wing elongate. 

 The scapular vein is much less arcuate than in the preceding 

 species and has a comparatively small number of distant, singly 

 or doubly forked, oblique branches. The much less oblique 

 branches of the internomedian vein are more frequent but appear 

 less crowded from their simplicit}', while those of the externo- 

 median are more distant than the latter, and equally simple. 

 There is no sign of any cross-venation. This species, like the 

 preceding, is small, the wing measuring about 12 mm. long, and 

 4*5 mm. broad. Named after Prof. Arthur Lakes of the School 

 of Mines at Golden, Colorado, the first discoverer of these 

 fossils. 



Triassic beds near Fairplay, Colorado. 



