CLASSIFICATION OF PALEOZOIC INSECTS. 343 



Polyernus (iroXw, epvos) gon. uov. 



i 



Body apparently of moderate stoutness, the wings large and rather broad, well rounded. 

 Mediastinal vein at a tolerable distance from the front margin, to which it sends many curv- 

 ing branches, and extending nearly to the tip of the wing. Scapular vein with three or 

 four distant, inequidistant, but very longitudinal, and therefore closely crowded, ramose 

 branches, the lowermost falling but little below the tip of the wing. Externomedian nu- 

 merously branched but less ramose, of about equal importance with the preceding. Inter- 

 nomedian with numerous inferior, mostly simple branches, occupying the middle half of 

 the lower margin. Anal veins similar. 



Polyernus complanatus, sp. nov. PI. 32, figs. 8, LI. 



The pr-othorax forms a sort of depressed shield like that of a cockroach, and is tolerably 

 well preserved, showing that it was subquadrangular, narrowing anteriorly, with well 

 rounded front and rounded posterior angles, a little broader than long, the posterior margin 

 convex; the whole surface was rugose, hut especially over a large, subcentral but poste- 

 rior, subcircular boss, the east of which shows a depression tilled with coarse, low granules. 

 The wings are very large and long, evidently extending far beyond the tip of the abdomen, 

 and overlapping, in the single example known, so that it is difficult to separate them, or to 

 distinguish certainly to which wing each belongs. From a careful study, however, it 

 would appear that the mediastinal extends nearly or quite to the tip of the wing (which is 

 lost) ; that the scapular throws off three long and slightly curving, forked, or multiple 

 forked, offshoots ; and the externomedian three or four more oblique, but not more curv- 

 ing, simple, or simply forked, branches. Length of prothorax, 7 mm., breadth of same, 

 9 mm., breadth of mesothorax, 9.5 mm., length of fragment of wing, 36 mm., probable 

 length of wing, 46 mm., apparent breadth of the same, 12 to 14 mm. 



Mazon Creek, 111. Received from Mr. R. D. Lacoe, No. 2058. 



Polyernus iaminarum. sp. nov. PI. 31, tig. 1. 



The four overlapping wings are alone preserved, the base lost and the whole somewhat 

 obscure ; the tips of all are roundly pointed. The mediastinal vein is much farther re- 

 moved from the margin in the hind than in the front wing, and shorter ; in the front wing it 

 reaches only 'he rapidly declivent portion of the margin before the tip ; the branches both 

 of the scapular ami externomedian veins have a strong, but graceful, downward sweep in 

 the apical third of the wing ; and the two basal offshoots of the former are forked just on 

 a line (slightly oblique) with the singly forking externomedian branches, and just before 

 the commencement of the downward curve of the nervules ; the outer branches of the 

 scapular vein are very ramose, in rather strong contrast to the simple forking of the exter- 

 nomedian branches. Length of fragment 50 mm., breadth of same 30 mm., probable 

 Length of wing 65 nun., its probable breadth 23 mm. 



A single specimen and its reverse, Nos. 2012. 2013, were received from Mr. R. D. Lacoe. 

 They are from a thin shale interleaved in the conglomerate near Pittston, Penn. (No. xu 

 of Roger's Survey of Penn.), and very near its base, there being but six or eight feet of 

 coarse pebbly rock between this shale and the "red shales" beneath. 



