10G Dr. A. S. Packard, Jr's Revision of the 



thorax finely punctured, two high and prominent sub mesial ridges, 

 parapsidal groove present, at each anterior augle of the scuteilum a 

 yellow dot; meta-scutellum smooth, polished, not punctured, with a 

 broad yellow stripe, interrupted by a deep square sinus behind. Sculp- 

 turing of propodeum closely approaches that of 0. atriceps ; enclosure 

 of propodeum distinctly lunate, at base a row of pits, succeeded by 

 fine radiating rugulae; mesial furrow narrow, widening posteriorly 

 where the segment is squarely docked, the posterior face vertical, 

 presenting a trapezoidal face, and bounded above and on the sides by 

 well defined ridges. Tubercle yellow, wings pale, not clouded, ner- 

 vures dark, dull ferruginous, pieces at the insertion of the wing 

 blackish. 



Femora black, ferruginous at tip in front, behind a yellow dot; 

 tibia; yellow, black within, bordered with ferruginous in front, espe- 

 cially on the anterior pair; posterior tibiae almost entirely yellow, black 

 brown at tip; tarsi all of a peculiar dull, glaucous, testaceous hue, 

 with a fine hirsuties, concolorous with the tibial spurs, while the joints 

 are slightly tipped with a bright ferruginous, polished tint. 



Abdomen broadly ovate, flattened above, below concave, smooth, 

 polished ; with four pairs of fasciae on second to fifth rings. The first 

 pair are longest, being hardly sinuate, second pair are farthest apart, 

 second and third are equal in size, fourth larger, broader, more orbi- 

 cular and nearly contiguous; tip mucrouate, triangular, at base not 

 quite one-half as broad as long, being suddenly contracted at the mid- 

 dle, and deeply channelled towards the extremity ; slightly hirsute, 

 posterior edges of rings with a few scattered hairs. 



Length of body, .83; head and thorax, .18; abdomen, .15 inch. 



Illinois, (Coll. Ent. Soc. Phil). 



Compared with C. atriceps this species has a longer and narrower 

 head, the peculiar carination of the prothorax is sharper, while the 

 sculpturing of the thorax is otherwise much the same; the tibiae are 

 stouter and very differently colored, while both agree closely in the 

 coloration of the abdomen, though the tip of the present species is 

 narrower and longer than in C. atriceps, which last varies greatly in 

 the relative size and distance apart of the abdominal fasciae. 



It may also be known by its unusually cubical head, the yellow cly- 

 peal region ; its two submesial ridges on the scutum, its finely striated 

 enclosure on the propodeum, and want of fasciae on the basal ring of 

 the abdomen. 



From C. montanus it also differs, while similar in abdominal characters, 



