Mr. S. H. Scudder on Mesozoic Gockroaches. 59 



millim. ; probable length of wing 9 millim. ; breadth of wing 

 3*5 millim. 



Triassic beds near Fairplay, Colorado. 



Neorthrohlattina Lakesii, sp. nov. 



Several specimens of this species were found. The costal 

 margin is arched, as in the last species, and the inner margin 

 has an almost equal opposite curvature. The externomedian 

 vein has a very sinuous course, and forks before the middle 

 of the wing with abundant neuration, occupying on the mar- 

 gin the entire tip of the wing and almost the outer half of the 

 lower margin, while the internomedian is reduced to an arching 

 vein, extending but little beyond the anal furrow, and with 

 only two or three branches ; the anal veins are all parallel to 

 the anal furrow and simple. Length of wing 9 millim. ; 

 breadth 3*5 millim. 



Triassic beds near Fairplay, Colorado. 



This species is named after Prof. Arthur Lakes, of the 

 School of Mines in Golden, Colorado, who first made known 

 these beds, this species being one of the first discovered 

 by him. 



Neorthrohlattina rotundata, sp. nov. 



The costal margin in this species is very strongly arched, 

 while the inner margin is straight, giving a very different 

 aspect to the wii^g. It closely resembles the preceding species 

 in the mediastino-scapular and anal areas, and also in the 

 peculiarities of the externomedian vein, excepting that the 

 latter does not encroach to so large a degree upon the interno- 

 median, the terminal offshoot of which creeps along the border 

 so as to limit the marginal extent of the externomedian area 

 almost as much below as above, although the branching of 

 the externomedian vein is scarcely lessened. Length of wing 

 8*5 millim. ; breadth 3*3 millim. 



Triassic beds near Fairplay, Colorado. 



Neorthrohlattina attenuata, sp. nov. 



This species departs from the typical forms in its slender- 

 ness and pointed apex, but it agrees so fairly in general 

 structure that it would best be placed here. The costal 

 margin is not regularly arched, being flattened mesially, 

 while the whole wing tapers beyond tlie basal third ; the 

 inner margin is also arcuate, and the tip bluntly pointed. 

 The mediastino-scapular vein terminates considerably before 

 the apex, and the oppositely arcuate internomedian reaches 



