S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 45 



end of the mediastinal area, and about opposite the origin of the last scapular branch ; 

 the anal veins are numerous and crowded, the first deeply forked and basally distant from 

 the furrow, the others simple and all slightly arcuate and subparallel to the basal half of 

 the furrow. 



The single known fragment represents a tolerably large species, the breadth of the wing 

 being 13.5 mm., while its length may be estimated as anywhere from 24 to 30 mm., the 

 actual length of the fragment being 19 mm. and the breadth to the length about as 1 : 2. 

 It is the under surface of a left wing which is exposed, in which all the veins and branches 

 of the costal half (namely those of the mediastinal and scapular areas) are prominent, while 

 all the others are very obscure, and as the obscurity affects to some degree the anal furrow, 

 it is probably entirely due to the preservation ; by favorable light and on careful examina- 

 tion, slight indications of transverse wrinklings may be seen in the scapular area, but there 

 could have been no regular nor definite reticulation. 



The species, which is peculiar for its breadth and the slight tendency of its branches to 

 subdivide, appears at first glance to have considerable resemblance to My I. Heeri ; but it is 

 certainly distinct from that by the stronger curvature of the anal furrow and consequent 

 abbreviation of the anal area ; it also differs by the sinuosity of the scapular vein, the 

 more -arcuate line of separation between the mediastinal and scapular areas and the more 

 crowded branches of at least these areas. From Myl. anthracophilum it may be distin- 

 guished by the lack of the strong deflection of the base of the principal veins, by its less 

 crowded venation, simpler branches and by the direction of the branching portion of the 

 scapular vein, which is parallel to the border in this species, but converges toward it in 

 Myl. anthracophilum. 



A single specimen, marked No. 284 by the discoverer, Mr. I. F. Mansfield, was found at 

 Cannelton, Beaver Co., Penn., in dark sandy shale immediately under a vein of cannel coal 

 known as the vein C of Professor Lesley. It is partly covered by a leaflet of Sphenophyl- 

 lum •Schlotheimii. Lower coal measures of Penn. 



Mylacris anthracophilum. PI. 5, figs. 6-8. 



Mylacris anthracophila Scudd., in Worth. Geol. Surv. 111., in, 568-70, figs. 5, 6. 



Fore wing. The wing is very broad at the base and tapers almost from the base by the 

 slope of the costal margin, which is strongly and regularly arcuate, while the inner margin 

 is nearly straight, bringing the rounded but rather produced apex in the lower longitudinal 

 half of the wing; the extreme apex is broken. The veins originate below the middle of 

 the base and curve strongly upward before assuming a more longitudinal direction, when 

 all are subparallel to the costal margin. The limitation between the mediastinal and 

 scapular areas is strongly arcuate basally, straight apically, and the mediastinal vein termi- 

 nates at the end of the apical three-fifths of the wing; the mediastinal branches, three or 

 four in number, most of them forked, are straight or very gently arcuate, and radiate from 

 a common point near the middle of the base of the wing, some of them plainly emitted 

 from the principal vein just beyond the base, and one from the same at a considerable 

 distance from the base. The scapular vein is strongly arcuate at, the base, but, next the 

 last branching of the mediastinal vein, takes a nearly straight longitudinal direction, sub- 

 parallel to but slightly converging toward the costal margin, and terminates near or at 



