392 Dr. A. S. Packard, Jr's Revision of the 



than mentioned by Say, though otherwise agreeing with his descrip- 

 tion. 



It may be recognized as being by far the largest species of this sub- 

 family as yet known to us; also by the head being punctured on the 

 vertex as much as on the front. On the meso-scutum the rucrse diverge 

 from the mesial slightly impressed line, so as to become transverse, and 

 then go obliquely backwards; the broad, triangular enclosure of 

 the propodeum, have slightly curved sides, and the limbus, which 

 in Cemonus is smooth and polished is here rugulose, while within are 

 large confluent punctures, or irregular fossulets ; the declivity of the 

 propodeum is puncto-striated, and on the tip of the abdomen is a long 

 narrow channel, with even, parallel sides. 



Length of body, .48 ; head and thorax, .22 ; abdomen, .20 inch. 



"Dublin N. H. Leonard," (Harr. Coll.). 



I cannot as yet perceive any valid characters sufficient to separate 

 the specimen from New Hampshire and that labelled P.morio, Cresson, 

 from Colorado. In that last specimen, the abdomen is much con- 

 tracted, the tip is drawn in, and thus the groove is partially concealed; 

 owing to this, the abdomen in the type specimen, loaned me by Mr. 

 Cresson, seems shorter than it really is, and the pedicel proportionally 

 longer — but I think the two species will have to be united. 



DIODONTUS, Curtis. 



Diodontus, Curtis, Brit. Ent. ii. p. 496. (1S36). 



9 . Head large, very cubical, with square edges, and eyes much as 

 in Passalsecus, but a litttle broader, though much farther apart on the 

 vertex; ocelli very contiguous, as in Passalsecus, but not so prominent. 

 Front much shorter and broader than in the succeeding genus, anten- 

 nae inserted much farther apart, and nearer the middle of the front 

 which is more concave at the origin of the antennae than usual; cly- 

 peus convex posteriorly, surface convex, smooth and polished, 

 acutely tridentate on the front edge; central tooth largest; labrum 

 exserted, edge broad emarginate, distinctly bideutate; mandibles very 

 long and slender, narrow, tips not widened, blunt, scarcely bidentate, 

 tips crossed; lower edge with a few long coarse setaa. Palpi long 

 narrow cylindrical, closely resembling those of Passalsecus, but tbe 

 joints are a little shorter and considerably stouter, especially the 4th 

 joint of the labial palpi. Antennae much as in Passalsecus, but the 

 scape is much shorter and thicker, flagellum equally clavate. Thorax 

 as in Passalsecus, prothorax angular on its sides, mesonotum much 

 more convex, smooth and polished; size of scutelluni and meta-scutel- 



