S. H. SCTTDDER ON PALAEOZOIC COCKROACHES. 121 



point where it diverges from its first course, which is doubly forked ; the next, which is 

 forked, at the end of the basal third of the wins ; and three simple, more closely approxi- 

 mated veins, at and a little beyond the middle of the wing. The externomedian has an 

 arcuate course, closely parallel to the scapular vein, through the basal third or thereabouts; 

 here it is broken up into three principal stems, the upper of which runs in a slightly arcu- 

 ate course to a point as far below the extreme apex as the scapular vein is above it, emit- 

 ting in the apical third of the wing three simple, nearly longitudinal branches, which 

 occupy the apex of the wing ; the middle stem runs close to the preceding, and emits, at 

 one-third and two-thirds way to the border, two superior, simple, straight, and nearly lon- 

 gitudinal branches; the lower is basally forked, the forks resembling the basal branch of 

 the middle stem. The internomedian vein is rather gently and regularly arcuate, termi- 

 nating next the middle of the lower border ; it has three simple branches, and one (the 

 first) forked branch, approximate, straight, and oblique. The anal furrow is a little more 

 strongly, but just as regularly arcuate, and strikes the margin at the end of the basal third 

 of the wing ; the anal veins, four in number, are simple, distant, slightly divergent, and 

 similarly arcuate. 



The wing is of medium size, but appears rather small from its narrowness, the fragment 

 measuring 22 mm. in length and 6.5 mm. in breadth; 1 the wing must have measured 

 23.5 mm. in length, so that the breadth was to the length as 1 : 3.6. If the upper surface 

 is preserved, it is from the left side. It is very nearly perfect, only a portion of the tip 

 and lower apical margin being lost. The reticulation between the veins is mostly de- 

 stroyed, but with a glass one may see. particularly in the anal area, excessively delicate 

 wrinkles or little streaks, giving a shagreened appearance to the wing, and indicating the 

 presence of closely crowded cross neuration. 



Heer remarks that this species comes next to Gej~abl. Milnsteri, but it differs more from 

 that than from many other species, such as Etobl. flabellata and Etobl. qffinis; but 

 even from these it is widely different in the distribution of the scapular and externomedian 

 branches. From its single congener, Progon. heloetica, it is readily distinguished by its 

 exceedingly different size and shape, and differs also in its broader mediastinal field, the 

 less basal division of the scarjular and externomedian veins, and the more oblique course of 

 the scapular branches. Indeed, it differs so much from it, that were it not for its essential 

 agreement in the points in which they both differ from the other palaeozoic cockroaches, it 

 would seem more rational to separate them generically ; which a more extended acquaint- 

 ance with palaeozoic Blattinarians may yet compel us to do. 



One specimen, from the coal-measures of Manebach, near Ilmenau, in Thiiringen. Upper 

 carboniferous. 



Oryctoblattina now gen. (dpuxriq, Blattina). 



Blattina Auct. (pars). 



The mediastinal vein of the front wings runs parallel and very close to the costal margin, 

 closer than in any other of the genera here described, and terminates only a little before 

 the middle of the outer half of the wing ; it emits numerous branches almost transverse to 

 the wing in the basal portion, but notwithstanding their brevity often forked in this part 

 of the area. The scapular vein is very peculiar ; it begins to branch a little beyond the 



1 Heer says 7.5 mm., but his figure represents it as if it were 6.5 mm., and this is mure likely to be correct. 



MEMOIRS BJST. SOC. NAT. HIST. VOL. III. 16 



