S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 85 



emits a large number of oblique, generally forked, straight, and nearly parallel branches. 

 Tbe scapular vein is very strongly arcuate, parallel almost throughout to the costal margin, 

 terminating beyond tne apex ; it is rather distant from the mediastinal and extemomedian 

 veins until it begins to divide, at about the middle of the Aving; here, a"nd a little further 

 on, it sends forth a couple of compound branches, besides a short, apical, simple shoot ; the 

 earlier forks of the compound branches have a direction similar to the mediastinal veins, while 

 the later are longitudinal. The extemomedian vein follows closeby parallel to the scapular 

 vein, and emits only two branches, superior, simple, and nearly straight, near together, and 

 only a little way beyond the branching of the scapular vein ; consequently this area occu- 

 pies only a narrow space at the extremity of the inner border ; somewhat before the middle 

 of tbe wing this vein is connected with those on either side of it by a pair of short, oblique, 

 cross veins, having the same direction as the internomedian branches. The internomedian 

 vein is even more strongly arcuate than the preceding, and very regularly curved ; in the 

 part which is preserved, and beyond the basal fourth, it emits four equidistant, nearly 

 straight, parallel and oblique, simple branches (they are represented as too sinuous in the 

 plate), and there are probably several others in the apical portion. The anal furrow is not 

 deeply impressed, is very strongly and regularly arcuate, and probably terminates a little 

 before the middle of the wing ; there are half a dozen anal branches, mostly simple and 

 oblique, and straight or arcuate, those next the furrow about as widely separated as the 

 internomedian branches, the others more closely crowded. 



The insect is of medium size, the wing being 23 mm. long, and the breadth of the frag- 

 ment 10 mm. ; probably the entire width of the middle of the wing, where it was presuma- 

 bly the widest, was 11.5 mm. and the breadth to the length as 1 : 2. The specimen is not 

 very per-fect, being partially overlaid by the frond of a fern, by which the lower apical half 

 is obscured, excepting most of the longitudinal branches of the scapular and extemomedian 

 veins ; the extreme base is also broken ; if the upper surface is that exposed, it is a right 

 wing ; all the interspaces of the wing, excepting in the mediastinal area, are traversed by 

 delicate cross veins closely approximated. The shape of the wing at once separates this 

 species from Arch, parallelum. 



The single specimen known was found by Mr. James Barnes, at the East River of Pictou, 

 Nova Scotia, in shale overlying the roof of tbe main seam of Pictou coal. 1 owe an 

 opportunity of examining it to Principal Dawson. Middle coal formation. 



Archimylacris parallelum nov. sp. PI. G, fig. 6. 



The fore wing is very equal, the larger part of both costal and inner margins being 

 straight and very nearly parallel, the wing tapering only in a very slight degree until near 

 the tip ; the anal angle is broadly rounded, and very similar in this respect to the humeral 

 lobe ; the extremity of the wing is broken, so that the form of the wing cannot be stated ; 

 the veins originate a little above the middle of the base, and curve upward as they pass 

 outward. The mediastinal vein runs subparallel to the costal margin, but gradually 

 approaches it throughout (hardly so represented on the plate), until about the middle of 

 the wing, when it curves rather rapidly to the border, terminating at some distance beyond 

 the middle ; it occupies less than a fourth tbe breadth of the wing, and emits, mostly in its 

 outer half, five or six oblique, forked, or simple branches. The scapular vein, beyond its 



