92 



S. II. SCUDDER ON PALAEOZOIC COCKROACHES. 



Anthracoblattina dresdensis. (See figure in text.) 



Blattina dresdensis Gein.-Deichm., Sitzungsb. naturw. Gesellsch. Isis, 1879, 12-13, figs. 



The fore wing is elliptical and very regularly formed, broadest in the middle ; the costal 

 margin is pretty strongly convex, especially on the basal half; the inner margin much 

 straighter, and the tip well rounded. The veins originate a little above the middle of the 

 wing, and curve gently upward before assuming a longitudinal course. The mediastinal 

 vein, beyond the basal fifth of the wing, is nearly straight, scarcely curving upward with a 

 broad sweep apically, and terminating only a little before the apex of the wing ; it emits 

 eight or nine rather closely crowded, nearly straight, oblique branches, about half of which 

 are simple, the others simply or doubly forked at or beyond the middle ; the area is 

 broadest a little before the middle of the wing, where it is one-third the width of the wing. 

 The scapular vein runs parallel and close to the mediastinal until it forks, a little beyond 

 the end of the basal third of the wing, and then turns downward in a 

 nearly straight course subparallel to the costal margin, to just below the tip 

 of the wing ; it emits three equidistant longitudinal branches, the first two 

 of which fork near the origin of the simple third, and embrace between 

 them the upper tip of the wing. The externomedian vein, beyond its 

 curved base, runs in an almost perfectly straight line to just below the ex- 

 treme tip of the wing, and, commencing to branch just before the middle 

 of the wing, or scarcely beyond the division of the scapular vein, it emits 

 four simple, inequidistant, arcuate branches, which (especially the basal 

 pair) are at first oblique and then longitudinal. The internomedian vein is 

 broadly sinuous in its course, being at first convex in the same sense as 

 the costal margins, afterwards, on parting from the anal furrow, in the oppo- 

 site sense, and terminates scarcely before the middle of the outer half of 

 the wing ; the area then diminishes rapidly in size, and is occupied by only 

 three or four straight, oblique, distant branches, none of which are long, 

 and which become continually shorter apically. The anal area is lost, as well as most of 

 the anal furrow, which apparently terminates not far from the end of the basal third of 

 the win?. 



The length of the wing is 28 mm.; its breadth 11 mm., and its breadth to its length as 

 1 : 2.5. It was therefore somewhat smaller than the average of the genus. The frag- 

 ment probably represents the upper surface of the left wing, and is nearly perfect, the 

 tip being broken in two places, and the entire anal area absent; the interspaces are 

 filled with a well-preserved reticulation of polyhedral cells. Geinitz compares this species 

 with Etobl. eufjlyiitica, and, although he mentions Anthracobl. porrecta, fails to see how 

 much more closely it resembles the latter species. Besides the differences he points out 

 in his comparison with the former, the stouter form of the wing and the inferior origin of 

 the externomedian branches should be mentioned. Of the species of Anthracoblattina, it 

 most nearly resembles A. porrecta, but differs from it in being less parallel-sided, in the 

 unequal width of the mediastinal area, the frequent forking of the mediastinal branches, 

 and especially in the more simple and regular branching of the scapular and externo- 

 median veins; besides these points, the scapular-externomedian interspace strikes the 

 margin below and not at the apex, and the internomedian branches are more distant. It 



Anthracoblattina 

 dresdensis. 



