S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 87 



areas, together with the vein next below it, are delicately raised, and probably represent 

 the apical branches of the mediastinal vein of the lower wing, while all the others are 

 distinctly impressed, and probably belong to tbe scapular vein. The former vein can be 

 traced (but is not represented on the plate) for a short distance, through the thickness of 

 the upper wing, running in a straight line toward the middle of that portion of the base of 

 the wing which is covered by the prothorax. 



Attached to the front wing is the pronotal shield, this being the only American fossil 

 cockroach in which this part is certainly known. It is of a very broadly and transversely ellip- 

 tical form, but, as preserved, does not have a perfectly regular outline, the curve of the left 

 side being uniform, while that of the right side would place the broadest part of the shield 

 a little behind the middle ; with this exception it is extremely regular, either lateral or 

 antero-posterior half being like its opposite. The surface is nearly flat and shows a cen- 

 trally disposed circular or elliptical furrow, irregularly subparallel to the margin, enclosing 

 a slightly convex central area, whose diameter is a little more than a third the breadth of 

 the pronotum ; the furrow is coarse and rather deeply impressed, but irregular from the 

 irregularities of the stone ; the posterior third of the shield is marked with faint, very 

 closely crowded, minute, straight, transverse wrinkles, crossing the whole pronotum. 

 Length, 7.5 mm. ; breadth, 10 mm. 



The parallel-sided front wing can by no possibility be confounded with that of Archim. 

 acadicum, with its strongly convex costal margin ; in this species the strongest part of the 

 curve of the veins is close to the base, as in most palaeozoic cockroaches ; but in Archim. 

 acadicum, it is at the middle of the wing, in conformity with its strong costal curve. 



The single specimen was obtained by Mr. I. F. Mansfield, at Cannelton, Beaver county, 

 Penn., in dark, sandy shale, immediately under the vein of Cannel coal referred to vein C 

 of Professor Lesley. Lower coal-measures of Pennsylvania. 



Anthracoblattina aov. gen. {av0pa%, Blattina). 



Blattina Auct (pars). 



The mediastinal vein of the front wing runs parallel to and generally rather distant 

 from the costal margin, terminating generally beyond, occasionally at the middle of the 

 apical half of the wing, and emits a large number of oblique, parallel, seldom forking 

 branches ; the area generally occupies nearly one-third of the breadth of the wing. The 

 scapular vein, sometimes curved near the base, is beyond that nearly straight, and termi- 

 nates shortly before or at the apex of the wing, — in a single instance [A. winteriana) 

 beyond it ; it never branches more than once, usually not at all, before the middle of the 

 wing, and the branches are usually longitudinal in appearance, although in all instances 

 actually superior, and seldom assume the appearance of similarity to those of the mediastinal 

 vein, as in Etoblattina; the branches are not numerous (more numerous in A. spectabilis 

 than in the others), and seldom fork more than once; owing to the length of the medias- 

 tinal area, the space occupied by this vein and its branches is very restricted, although not 

 more so than that occupied by the next vein. For the externomedian vein, which is sepa- 

 rated from the preceding by an equal interspace, on either side of which the branches of 

 the two areas diverge at equal angles, is usually a close counterpart in a reverse sense of 

 the scapular vein, excepting that the first offshoot is usually more important than the 

 others, often equalling, with its forks, the rest of the vein. The combined internomedian 

 and anal areas occupy fully half the breadth of the wing near the base, and, excepting in 



