and Sjiecies of Fossil Cockroaches. 409 



America ; and the Triassic genera and species are interesting, 

 not only from the deposit in which they occur, but also from 

 their relation to Carboniferous and Liassic types*. They 

 will all be figured on another occasion. 



PROMYLACRIS {Trp6j /Av\a/cpi<i) } nov. gen. 



The mediastinal vein, though large and abundantly sup- 

 plied with veins, terminates not far beyond the middle of the 

 wing ; most of the branches fork more than once ; the scapu- 

 lar vein runs in nearly a straight course, and terminates a 

 short distance beyond the mediastinal, playing a very insig- 

 nificant part ; the externo-median vein is far more important, 

 crowding back the scapular vein on the one side and the 

 externo-median on the other ; the anal furrow is very deeply 

 impressed and the anal area stongly convex, its veins regular, 

 frequent, and strongly curved. 



Promylacris ovalis } nov. sp. 



Represented by a single specimen and its reverse in a 

 nodule preserving well the anterior half of the body. The 

 pronotum is regularly arched, about one fourth as high as 

 broad, and twice as broad as long. The front wings have a 

 strongly developed humeral lobe and a costal margin of con- 

 siderable convexity. The mediastinal branches are clustered 

 into three groups ; the scapular vein is composed of only two 

 branches, each of which forks with slight divarication ; the 

 externo-median vein has three principal branches, all of which 

 originate far toward the base of the wing ; the interno-median 

 area is unusually small, apparently not reaching so far out 

 as the scapular area. The fragment is 20 millim. long, and 

 the wing 12 millim. broad, but it was probably about 29 millim. 

 long. 



Carboniferous deposits of Mazon Creek, 111. Received from 

 Mr. Wm. (iurley. 



Paromylacris (71-apos, fiv\uKpis) : nov. gen. 



The mediastinal vein consists of at least seven or eight 

 principal branches, several of them forking close to the base, 

 the outermost extending far toward the tip of the wing, making 

 this area unusually important ; the scapular is also important, 

 the main vein running through the middle of the wing in a 

 straight course to the tip ; the externo-median branches do not 



* Aruer. Jouru. Sc. (3) xxviii. pp. 19U et seq. 



