90 S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 



one-quarter the breadth of the wing in the middle. The scapular vein is differently repre- 

 sented in the two wings (of the same individual) figured by Geinitz; so differently indeed 

 that both can hardly be correct, and for our description we have chosen the one which 

 accords with the structure of the species evidently allied to this ; in this it runs at first 

 parallel to the costal border, as far as a little beyond the middle of the basal half of the wing, 

 where it forks ; its first branch is simple and continues in close proximity and parallel to 

 the mediastinal vein, while it itself runs in a nearly straight, longitudinal course, termi- 

 nating just before the extreme tip of the wing ; it emits three other simple branches, the 

 last one forking at the extreme tip, just beside an additional short apical branch of the main 

 stem. The externomedian vein, more strongly arcuate next the base, divides a very little 

 beyond the division of the preceding, and then runs parallel to that, emitting in all four 

 branches, the first forking in the middle, the others simple; and all longitudinal, closely 

 crowded, and together occupying an extremely narrow area on the margin at the extreme 

 apex of the wing. The internomedian vein runs parallel to the preceding vein and its 

 basal branch ; but somewhat beyond the middle of the wing, emits a supplemental superior 

 branch running nearly parallel to the main stem, and extending the area so much further 

 out, that it terminates as near the apex as the scapular area, and narrows very gradually; 

 commencing before the middle of the basal half of the wing it emits about eight nearly 

 straight, slightly sinuous, oblique branches, the basal ones simply or doubly forked, the 

 others simple, four or five of them emitted before the supplemental vein, the others beyond. 



Geinitz states, what his illustration bears out, that the second branch on this wing is forked 

 . . .... . . , * 



only at the end ; while in the opposite wing it is not only distinctly forked near the base ("nahe 



der Wurzel," but really at the end of its basal third), but one of the forks again divides at 



the tip. The anal furrow is rather deeply impressed on the arcuate basal half, lightly on. 



the straighter apical portion, and terminates at about the end of the second fifth of the 



wing ; the anal veins are arcuate, those next the furrow compound, the others simple, and 



all considerably and equally crowded. 



Here again Dr. Geinitz's illustration is at fault, the two wings differing considerably, the 

 anal area being undoubtedly too extended in the wing which we have not copied. Care 

 seems to have been taken only with the wing which does not overlie the body ; this is 

 altogether unfortunate in illustrating an insect which is undoubtedly the most perfect exam- 

 ple of a palaeozoic cockroach which has yet been found ; and the chance to observe the 

 differences between the two wings, as a basis for a distinction between individual and specific 

 differences, is lost, excepting in the points actually specified by Geinitz ; and as he particu- 

 larly remarks upon the value of the differences observed by him. it is the more probable 

 that the other differences, apparent on his plate, do not actually exist, for if they do they 

 are of much greater importance than those he specifies. 



The wing figured is a very large one, measuring 45 mm. in length, as stated by Geinitz 

 (in his plate it is 46.5 mm. long), and 20.5 mm. broad ; this he says is shorter than it should 

 be, the wing being contracted by a transverse wrinkling of the specimen, represented in his 

 plate by some wavy, transverse, narrow bands; the other wing is 50 mm. long and 20 mm. 

 broad, and represents, he thinks, the proper size ; it is not impossible, however, that the 

 wings may have actually varied H little in length, and the breadth to the length may be put 

 down as between 1 : 2.2 and 1 : 2.5. Both wings are nearly perfect, the apical edge of 

 each being lost for a little way, and a few of the veins being obscured. The wing we have 



