ARCHIMYLACRIS HASTATA. 103 



costal margin is shown, passing into a very broad and expanded apex. The 

 subcosta reaches nearly to the end of the costal margin, and gives off numerous 

 oblique and forked branches Immediately behind the subcosta is a stout vein 

 •with two outer branches, both forking. This vein seems to be the radius. Tts 

 basal extension under the tegmen can be traced by a raised line. Behind the 

 radius are two stout veins, each of which forks into equal-sized twigs some 

 distance from the margin. Their position justifies the inference that they unite 

 proximally and join the radius, in which case they must belong to the radial 

 sector. The median is a doubly forked vein. The remainder of the wing is 

 either bent under, or folded upon itself, and further details cannot be made out. 



Affinities. — The species differs from Aphthoroblattinajohnsoni in several important 

 details. The radial sector arises further out, and instead of forking twice, gives 

 off three simple forward veins. The median forks three times, the proximal 

 branch forking again before reaching the wing-apex. In A. jolmsoni there are two 

 branches, both of which fork. The cubitus vein differs considerably owing to the 

 fact that the main stem divides at the outer third into two branches of equal 

 strength, the outer immediately forking again into two equal twigs, while the 

 inner gives off a small inner twig. No definite outer branches are distinguishable. 

 A strong anal furrow is present, and the first anal vein on both sides divides into 

 three twigs, the remaining 5 — 6 anal veins being undivided. 



Genus ARCHIMYLACRIS, Scudder. 

 1868. Archimylacris, Scudder, in Dawson's Acadian Geology, ed. 2, p. 388. 



Generic Characters. — Tegmina twice as long as wide, with convex outer margin. 

 Inner margin concave. Radial sector ainsing in basal half of wing. Anal veins 

 few, anal area large. Neuration of abundant stout straight cross-nervures. 



Archimylacris hastata, Bolton. Plate VII, fig. 1 ; Text-figure 33. 



1911. Archimylacris (Efoblattina) hastata, Bolton, Quart. Journ. Geol. Soc, vol. Ixvii, p. 160, pi. ix, 

 figs. 1—3. 



Type. — The greater part of a left tegmen and its counterpart, showing the 

 upper surface; Museum of Practical Geology, Jermyn Street (nos. 24501 and 24502). 



Horizon and Locality.— Upper Coal Measures (Gellideg Level of the Mynyd- 

 dislwyn Vein) ; near Maes-y-cwmmer, Monmouthshire. 



Specific Characters. — Wing broadly elliptical. Costal margin convex ; costal 

 area broad at base and stretching beyond the middle of the wing. Subcosta 

 with numerous branches, all oblique. Radius forking twice, and ending near 



