114 S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 



pie, are thrown off, one opposite the first fork of the first branch, the other opposite the 

 last branch of the scapular vein ; there is also the commencement of an oblique, stout 

 cross-vein opposite the basal branch of the scapular vein, running half way to the second 

 branch of the internomedian vein, almost precisely similar to what occurs in Etobl. venusia, 

 and in Arch, acadicum, both, like this, American species, and members of the same sub- 

 family. The internomedian vein and anal furrow part from each other almost immediately 

 after their common departure from the united vein, and the internomedian then runs in an 

 irregularly straight line, subparallel to the externomedian vein, and terminates a little 

 further from the tip than the mediastinal vein ; it curves downward a very little at the 

 origin of its third branch, so as to be a little more distant from the externomedian between 

 its third and fourth branches than before ; it has in all five branches, which originate at 

 subequidistant intervals, the last of which is simple, the others more or less deeply and 

 simply forked; they are all more or less arcuate and somewhat longitudinally oblique. The 

 anal furrow, from the common origin of all the veins, is straight, very deeply impressed on 

 the basal half, somewhat longitudinally oblique, and terminates in the middle of the inner 

 margin; 1 the anal veins are very independent of the anal furrow, consisting first of a pair 

 of compound veins arising from the extreme base of the wing at the origin of the common 

 stem of the principal veins, and running in an obliquely longitudinal course to strike the 

 apical half of the margin of the anal area, and leaving a wide interval at the base between 

 them and the common stem and the anal furrow ; and in the angle four closely approxi- 

 mated, straight, similarly oblique, simple veins. 



The wing is a large one, measuring 35 mm. long as far as preserved, and 15.5 mm. 

 broad ; the entire length of the wing must have been 38 mm., and the proportion of the 

 breadth to the length as 1 : 2.5. The wing is perfect, except a slight fragment of the tip and 

 a little piece of the base of the anal area. The specimen shows the upper surface of a left 

 wing. The surface is covered with a very delicate network of raised veins, which are 

 arranged more or less irregularly, transverse to the interspaces, in a broad marginal band 

 around the apex and inner border of the wing, and as an entirely irregular polygonal retic- 

 ulation upon the disc ; no network can be seen, probably from poor preservation, upon the 

 mediastinal area. 



This species was wrongly compared by me to Etobl. primaeva, with which it has very few 

 special points in common, and from which it is widely distinct in the structure of the medi- 

 astinal and anal veins. It seems to belong certainly in the genus Gerablattina, but forms 

 perhaps a distinct section, differing from all others in the extreme multiplicity of the medias- 

 tinal branches, in the basal coalescence of the other principal veins, in the arborescent 

 division of the scapular and externomedian veins, and in the longitudinality and dichotomy 

 of the anal veins, and their wide separation from the anal furrow. In the broad features of 

 its neuration, however, and particularly in points of division of the scapular, externo- 

 median, and internomedian areas, it resembles most and to a considerable degree the only 

 other American species of the genus, G. balteata, but it differs from it in all the points 

 above mentioned, and in lacking the banded ornamentation of the veins. 



The single specimen found was obtained by Mr. E. D. Lacoe, at Pittston, Penn., and lies 

 on a piece of black carbonaceous shale coming from the interconglomerate beds of the true 



1 The termination of the anal area is marked in the plate on the wrong side of the anal vein. 



