(.52 SAMUEL II. SCUDDER ON 



many this part is no! preserved ) a strong tendency to run in a similarly longitudinal course, 

 so that they trend from different parts of the area toward the outer lower extremity of 

 the area, where they are closely clustered. This is an approach toward the generally 



longitudinal course of the anal veins in recent cockroaches, where they abut upon the 

 anal furrow and not on the margin. The genus stands midway between Rithma and 

 Elisama, the latter being a genus in which the peculiar course of the median veins is more 

 conspicuous than here, but which has no such large anal area as is common to the 

 species of this genus. Mesoblattina is for more abundant in species than any other meso- 

 zoic genus, being found in considerable abundance both in the Lias and in the Oolite, 

 but especially in the latter. The species may be separated into two groups. 



1. The anal veins are parallel and end on the man/ in at equal distances apart. 



Mesoblattina Blakei sp. » v. 



PI. 46, fig. 12. 



A single wing from which a considerable portion of the tip is lost, but which shows 

 all the characteristic parts of the neuration almost completely. As restored on the plate, 

 the wing is exceedingly slender, nearly four times as long as broad, with very parallel 

 .•-ides, the costal border gently arcuate, flattened in the middle and the inner margin 

 nearly straight. The humeral field is very long, lancet-shaped, extending nearly to the 

 middle of the wing. The mediastino-seapular vein is exceedingly sinuous, the area being 

 broadest opposite the tip of the humeral field, where it is nearly half of the breadth of 

 the wing, and extending (probably) only a little distance beyond the middle of the outer 

 half of the wing; the nervules are oblique, simple, parallel, tolerably abundant. The ex- 

 ternomedian vein first forks somewhat before the middle of the wing and has long, so far 

 as can be seen simple, wholly longitudinal, or upward curving branches which trend so 

 as probably to terminate on the tapering apex of the wing wholly above the middle line; 

 probably they fork near the tip. The internomedian vein is divided back of the first 

 forking of the externomedian into two branches, the upper of which forks near the mid- 

 dle of the wing and resembles one of the externomedian offshoots; the other has three 

 or four inferior, sinuous, very longitudinal branches, all impinging on the outer half of 

 the lower margin and rather more closely crowded than the costal nervules. The anal 

 area is very large, extending very nearly as far out as the humeral field; the anal furrow 

 is depressed, very uniformly arcuate, and the anal veins are very peculiar, appearing to 

 consist of a mid-vein parallel to the anal furrow, dividing the area into two nearly 

 equal halves and furnished with longitudinally oblique parallel nervules which appear to 

 terminate at equidistant points on the margin; and second, of a single slight vein midway 

 I ict ween the first and the anal furrow, the 1 termination of which is uncertain since the 

 outer lower half of the anal area is broken away, revealing beneath the very closely ap- 

 proximated, parallel, oblique offshoots of (probably) the anal area of the hind wing. 



Length of fragment 15 mm.; probable length of wing 19 mm.; width 5 mm. In the 

 structure of the anal area this wing is totally different from any other species. It comes 

 from the Upper Lias of Alderton, Gloucestershire, England, and was sent me by Rev. 



