SELLARDS. | Cockroaches. 505 
types is united at the base with the radius and subcosta. The 
cubitus, on the contrary, is free from all other veins and at the 
base turns down toward the inner border, as do the trachea 
in the wings of nymphs. That this is the normal course of the 
cubitus is evident from its occurrence in several species. Fol- 
lowing the cubitus the first anal vein is usually simple, but 
occasionally gives off one or two inferior branches. Its trachea 
is strong to the base and, like that of the cubitus, turns to- 
ward the ventral side of the wing. The second anal vein 
normally gives off a few inferior branches resembling those of 
the cubitus. The trachea of this vein also is free to the base. 
Formerly the writer was of the view that the fold in the 
hind wing of cockroaches, while present among the Permian 
species, had not developed as early as Coal Measure time. Eu- 
ropean writers have, however, illustrated specimens which 
leave apparently no doubt that the fold in the wing was present 
as early as Coal Measure time. 
Order ORTHOPTERA. 
Superfamily BLATTACHA Sellards. 
Family PALHOBLATTIDA# (Paleoblattariz Scudder). 
Mylacris SCUDDER. 
Geol. Survey of Illinois, vol. 3, p. 568, 1868. : 
One species only of the genus Mylacris has been found in the 
Kansas deposits. The genus as employed by Scudder is dis- 
tinguished from other genera of the Mylacrinariz by the com- 
paratively large area occupied by the subcostal and radial 
areas, the subcostal especially being large, defined as larger 
than the radial. In general, broad-winged species with sub- 
costal area large as compared with the radial are referred to 
this genus. Mylacris has not been found in the Permian, the 
species here described from the Upper Coal Measures being the 
latest of the genus known. 
Mylacris latissima sp. nov. Pl. LXXI, fig. 5; pl. LX XXII, fig. °2. 
Tegmina very broad in proportion to the length; widest at 
the middle of the anal area. Costal and inner borders both 
slightly arched, sloping gradually to an obtuse apex placed in 
about the center line of the wing. Subcostal area broad, 
extending to about the middle line of the wing; two main 
branches are distinguishable. The radial area extends to near 
