S. H. SCUDDEK ON PALAEOZOIC COCKROACHES. 53 



The genus differs from the two preceding by the smaller extent, both in breadth and 

 length, of the combined mediastinal and scapular areas ; from both also, but particularly 

 from Lithomvlacris, in the great extent of the externomedian area. The species are of 

 large size, including the largest American forms, and are unknown to Europe. 



Necymylacris lacoanum nov. sp. PL 5, fig. 12. 



Fore wing. The form is indeterminable from the only fragment known, although it is 

 probably proportionally shorter than in Nee. heros ; the veins are all strongly curved at the 

 base. The mediastinal area is less extensive than in the other species of the genus, and 

 resembles the other genera of Mylacridae to a greater extent in a more radiate disposition 

 of the veins, at least four in number, of which the last has at least three rather distant and 

 apparently simple branches, the outermost originating at some distance beyond the first 

 division of the scapular and internomedian veins; probably the area does not extend 

 beyond the middle of the wing. The scapular vein lias a rather strongly sinuous curve 

 and at least three straight and simple branches, of which the first, probably arising in the 

 middle of the basal half of the wing, is in direct continuation of the basal portion of the 

 vein, and thus separates the scapular from the mediastinal area by a straight line ; the 

 branches are parallel to the outer of the mediastinal veins, and the area, which is certainly 

 broad, probably more than a third of the breadth of the wing, extends no doubt nearly to 

 the tip of the wing. The externomedian vein beyond its basal curve is straight, and first 

 divides beyond the last (preserved) branch of the scapular vein, or, probably, shortly 

 before the middle of the wing ; it emits at least two superior branches, the simple bases 

 only of which are preserved in the specimen, but, from the divergence of these, the area 

 probably occupies the entire apex of the wing. The internomedian vein is regularly and 

 very strongly arcuate, probably terminating at some distance before the tip, and emits four 

 equidistant, well-separated branches, one of which is deeply forked, the others simple, all 

 straight or gently arcuate and very long, the area occupying apparently more than half of 

 the wing. The anal furrow is scarcely more distinct than one of the veins, and is nearly 

 as straight as they, appearing to originate from the internomedian vein near the base of the 

 wing, and terminating probably a little before the middle of the wing ; the anal veins are 

 numerous, especially toward the basal angle, gently arcuate, simple or forked, the outer 

 one very much curved, distant from the others, and compound. 



The wing is of medium size, the largest fragment measuring about 13 mm. long, and 

 the breadth of the two fragments when united nearly 12 mm. ; probably the entire length 

 of the wing was about 25 mm., and the breadth to the length as 1 : 2. It is a left wing, of 

 which the upper surface is exposed, but is very fragmentary and shattered, no part of the 

 border, unless in the unimportant anal area, being preserved ; probably nearly half of the 

 apex is gone, as well as a slight part of the base; the veins are delicately impressed, but 

 distinct, excepting toward the costal border, and the surface flat. and. at least in the 

 internomedian and anal areas, rather distinctly marked with very frequent transverse 

 wrinkles. 



Hind wing. Protruding from beneath the front wing is a small fragment of a hind wing, 

 apparently the apical lower portion of that of the opposite side of the body ; all that can 

 lie made out are about a dozen straight equidistant parallel veins, about half of them 

 (mostly those nearer the apex of the wing) forking simply; their direction, as they lie on 



