52 S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 



region also is flat, while the interspaces of the scapular and mediastinal areas, especially of 

 the former, are broadly sulcate (i. e., arched on upper surface) but much less so than in the 

 other species of the genus ; the surface seems to be completely smooth, is of a carbonaceous 

 black in the specimen, distinguishing it strikingly from the clay-colored matrix. The ex- 

 treme edge of the entire humeral lobe is marginate as far as the mediastinal veins. 



The wing is peculiar for the very large proportion which the mediastinal and anal areas 

 occupy to the rest of the wing, and for the extreme simplicity of the neuration, in which 

 there is not a single forked branch outside the mediastinal area ; the veins are very distant 

 and the species is at once distinguished from the others of the genus by the much stouter 

 shape of the wing, which is much less, while they are much more than three times as long 

 as broad. 



The single specimen discovered was obtained by Mr. Win. Gurley, from the coal meas- 

 ures of Illinois, about six miles from Danville, and sent me by him for study. Lower coal 

 measures of Illinois. 



Necymylacris nov. gen. (»£xv<;, /wlazpfe.) 



The mediastinal vein of the upper wing differs from the same vein in the other members 

 of this group, to judge at least from the most perfect specimen, in emitting from the outer- 

 most vein several branches at infrequent intervals, even to a long distance from the base ; 

 these branches may themselves be compound, so that a certain resemblance or approxima- 

 tion to Blattinariae may be seen ; but, in addition to these, there are the usual radiating 

 veins next the humeral lobe ; in the typical species, the only perfect specimen of the genus 

 known, the last vein terminates in the middle of the apical half of the wing, but in the 

 other it appears to be much shorter. The scapular vein, curved or bent before branching 

 (which it does near the end of the basal third of the wing) thereafter runs in a straight or 

 sinuous course to a little before the tip of the wing, emitting three or four veins which may 

 lie multiple-branched or perfectly single. The externomedian vein is forked a little before 

 the middle of the wing, and emits a number of forking branches, which, while they are longi- 

 tudinal in direction, are superior, so that the equal interspace between the externomedian 

 and internomedian veins is marked by oppositely diverging branches ; the externomedian 

 area occupies the entire or almost the entire apical border of the wing, so that it is of a 

 narrow wedge-shaped form. The internomedian area is apparently more extensive than 

 the anal, the anal furrow terminating on the inner margin nearly opposite the termination 

 of the mediastinal area and havingaratherobliquecurvingcour.se; the internomedian vein 

 emits five to ten branches, generally simple, occasionally forked at the base, and in one of 

 the species itself forks longitudinally not far beyond the middle, the upper fork dividing 

 near the tip and the lower emitting the apical branches ; these all run in a slightly curved 

 course more oblique than the anal furrow. The branches of the anal vein are numerous, 

 run more longitudinally, are more closely crowded toward the anal angle and fork feebly, 

 excepting the upper one which, though considerably curved, is well separated from the anal 

 furrow and emits several inferior branches. 



Besides upper wings, the slight fragment of a part of one of the lower wings has in one 

 instance been found, in which the veins of the apical portion are thickly crowded, straight 

 and parallel, and fork feebly toward their tip. 



