S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 99 



the upper two-thirds of the wing. The mediastinal area is nearly one-third the width of the 

 wing, the main vein running parallel with the costal margin for a long distance, probably 

 over the basal two-thirds of the wing, beginning to turn toward the border only at the very 

 extremity of the fragment, and probably reaching the border at no great distance before 

 the tip of the wing; it emits nearly a dozen distant, nearly straight, simple and oblique 

 branches. The scapular vein runs closely parallel to the preceding throughout the frag- 

 ment, supposing the two veins which appear to originate from its under surface to represent 

 the externomedian vein ; whether this interpretation is correct, neither the description nor 

 the illustration of Mahr enable us to state positively; but the resemblance of this wing to 

 others of the genus in which we place it renders it probable that here, as is usually the case 

 in the genus, the scapular is of less importance than the externomedian vein, and in such a 

 case only one of the three veins which lie between the mediastinal and internomedian veins 

 in the middle of the wing can belong to the scapular vein ; although this vein is simple in the 

 fragment, the turn of the mediastinal vein toward the costal border renders it nearly cer- 

 tain that it forks at least once or twice in the apical third of the wing. The externomedian 

 vein, on the same assumption, divides into two branches before the middle of the wing, 

 each of which again forks beyond the middle of the wing, and undoubtedly branches again 

 beyond that, probably occupying upon the margin all the space from a little above the tip 

 to the extremity of the internomedian area ; the general course of the vein is at first 

 strongly arcuate, afterwards longitudinal. The internomedian vein is strongly arched in 

 the basal half of the wing, then becomes straight or bent a little toward a longitudinal 

 direction, and probably terminates about as far from the tip as the mediastinal vein; it 

 emits only three branches, the first forked, the others simple, all gently arcuate, oblique, 

 and distant ; the veins of this area are represented by exceedingly heavy lines in Mahr's 

 illustration, but as he makes no mention of any difference between them and the others? 

 this is probably an error. The anal furrow is very strongly arcuate indeed and deeply im- 

 pressed, terminating, probably, a little before the middle of the wing; the anal veins, 

 according to Mahr, are ten in number, but many more are represented in his figure, 

 which is carefully followed in our plate; these are all arcuate, regular, simple, and, in 

 striking contrast to the other areas, closely crowded. 



The wing is of medium size, the length of the wing being 15.5 mm., while the entire 

 length of the wing is probably about 23 mm. ; its breadth is '•) mm., and the breadth to the 

 length as 1 : 2.55. From Mahr's statement that the anal field is concave, the under surface 

 is evidently exposed to view, and the wing is therefore a right one. 



It is remarkable for the great extent of its anal area, by which it is .readily separated 

 from all the species of the genus in which this area is known, and for the close proximity 

 of the veins in this area as contrasted with their wider separation in the rest of the wing ; 

 in the uniform belt-like nature of the mediastinal area it resembles several of the species', 

 particularly G. clathrata, G. intermedia, and G. Mahri ; from the first of these it is quickly 

 distinguished by the distance of the branches of the mediastinal vein, in which particular it 

 more nearly resembles the other species ; from G. Mahri it differs greatly in size and in 

 the convexity of the costal margin ; and from G. intermedia in the early division of the 

 externomedian vein and the strongly- curved internomedian vein. 



A single specimen, from an argillaceous schist between the third and fourth veins of the 

 Ihuenau coal basin, Manebach. Upper carboniferous. 



