,\ i j SAMUEL II. SCUDDER OX 



Ctenoblattina? pinna. 



["Without name.] Brodie, Foss. Ins. Eng., 118, PL 5, fig. 5. 



Blatta pinna Gieb., Ins. Yorw., 322. 



Blattidium pinna Ileer, Viertelj. naturf. Gesellsch. Zurich, 18G1, 290. 



This species appears to belong here, but I have not seen the specimen and the obscu- 

 rity of the drawing renders its location uncertain. It is badly broken at base, so that 

 tbe humeral angle and anal area are (probably) entirely obliterated. The fragment is 

 represented as nearly 4.5 mm. long, and its real length was probably about 5 mm. It 

 differs from the preceding species in the uniform width and greater extension of the cos- 

 tal area, which must reach the very tip of the wing, the apparent absence of spurious 

 nervules in the same area, the even slenderer externomedian area hardly expanding api- 

 call} T , and the very great width of the internomedian area, which occupies fully half of 

 the wing. 



It comes from the English Purbecks. 



'.- 



Neorthroblattixa Scudder. 



JSfeorthroUattina Scudder, Proc. Acad. Nat. Sc. Philad., 1885, 108. 



In this genus the wings are about two and a half times longer than broad, with fairly 

 well rounded apices, the costal area extending nearly to the tip, and in the middle of 

 the wing occupying nearly one-half its width. The internomedian vein is of varying 

 importance, and in the large anal area the veinlets terminate on the margin; the anal 

 furrow is strongly arcuate, and deeply impressed. 



All the species come from the American Trias. 



The four species are AT. albolineata, JV. Lahesi, N. rotundata and JS r . attenuata, all 

 found at Fairplay, Colorado. They were briefly described in the Philadelphia Academy's 

 Proceedings, and will be fully discussed and figured in a paper devoted to this Triassic 

 locality, so that it is only necessary here to indicate their apparent position in the series. 



ElTIIMA Giebel (emend.). 



Rithma Giebel, Ins. Vorw., 318; Scudd., Proc. Acad. Nat. Sc. Philad., 1885, 11:!. 



The wings of this group, as it is limited by me in the place above referred to, are gen- 

 erally rounded wedge-shaped, i.e., slender and tapering (though the latter peculiarity is 

 wanting in some even of the slenderest species) with the costal area large, occupying 

 nearly or quite half of the wing, the main vein sinuous, generally conspicuously sinu- 

 ous, rarely almost straight, terminating close to, sometimes even below, the tip. The 

 anal area is generally pretty large, vaulted, and filled with arcuate parallel veins which 

 terminate on the margin. The externomedian and internomedian veins are also sinuous 

 and divide the remaining space about equally between them, each forking considerably 

 and radiating apically. Their nervules, and especially those of the internomedian vein, 

 are rarely more longitudinal than oblique. The genus stands midway between Neor- 

 throblattina and Mesoblattina, the flatness of the humeral field, and the great extent of 



