446 TERTIARY INSECTS OF NORTH AMERICA. 



segment. Tibiae heavily spined. Whole body brownish fuscous, the cerium 

 of henielytra fusco-castaneous, the membrane scarcely infumated. 



Length, 5.1""; breadth, 3°'"'. 



Florissant. Two specimens, Nos. 441, 12998. 



4. Necrocydnus stygius. 



Head twice as broad as long, well rounded, two-fifths as broad as 

 the base of the thorax, the eyes large. Thorax onl}' twice as broad as its 

 median length, tapering considerably, the sides very regularly arcuate, the 

 lateral angles of front not jjrominent, the emargination of the apical border 

 somewhat less than half the length of the basal border, rtignlar, and very 

 shallow ; surface even, a little roughened. Scutelluni scarcely more than 

 half as wide as the thorax, almost equiangular, the sides perfectly straight, 

 reaching less than half-way to tiie apex of the abdomen, the surface appar- 

 ently punctate, but obscure. Corium of hemelytra reaching the middle of 

 the antepenultimate abdominal segment, punctate, the punctse serial only near 

 the sutura clavi. Tibiae heavily spined. Abdomen a little produced, so that 

 the posterior curve of the body is scarcely so broad as the anterior. 



Length, 6™" ; breadth, 3.5°"". 



Florissant. Two specimens, Nos. 6654, 9947. 



5. Necrocydnus amyzonus. 

 PI. 28, Fig. 16. 



Head rather small, I'ounded subtriangular, nearly or quite twice as 

 broad as long, hardly more than a fourth as broad as the thorax. Thorax 

 twice as broad as the median length, tapering considerably, with rather 

 strongly arcuate oblique sides, the lateral angles of the front not ^^rominent, 

 the apical emargination regular, considerable, rather deep, and very broad, 

 tiie surface of the thorax even and very finely and closely punctate. Scu- 

 tellum nearl}- as long as broad, fully two-thirds as broad as the thorax, tlie 

 apex reaching about half-way to the tip of the abdomen, the surface like 

 the thorax. Hemeh'tra with the corium reaching the penultimate abdominal 

 segment, feebly punctate. Legs densely spined. Abdomen broadly rounded. 

 Whole body uniformly blackish fuscous, the corium of hemelytra dark cas- 

 taneous, the membrane clear. 



