Fossorial ITymenoptera of North Aim rim. 77 



i 



black, greatly elongated, nearly as long as broad and ridged along the 



median line, edge rounded convex, antenna! groove very deep, suddenly 

 sunken below the surface of the triangular front; orbits densely silvery 

 pubescent, antennae broad and flattened, scape clavate, rapidly increasing 

 in width towards the end; joints of flagellum broad and flattened beneath, 



above convex, shorter than broad; terminal joint acutely conical, very 

 much smaller than usual, brown, scape yellowish towards the base. 



Thorax elongated ovate, wings appearing as if set far back owing 

 to the prolongation of the ineso-thorax, and the elongated prothorax, 

 which anteriorly is developed more than usual. Propodeum elongated, 

 the enclosure obsolete, median furrow narrow, on each side a net work 

 of small fossulets, the rugae enclosing them being straighter longitu- 

 dinally than the transverse ones ; entirely black except the yellow 

 tubercle. Fore femora yellow, with a black line at base ; trochanters 

 broadly dilated towards the tip ; femora twice dilated, so that the outer 

 edge is sinuate, near the base a small spine ; tibiae widened percep- 

 tibly towards the tip, but with no emarginate expansion; middle and 

 hind femora black, tibiae with a blackish stripe within ; tarsi yellow, 

 fuscous at tips. 



Abdomen very short, round, ovate, surface finely punctured, but 

 smooth and shining, basal joint broad, with five pairs of long oblong 

 fasciae, not obliquely arranged on the rings, but straight, and a little 

 farther apart than usual. 



Length of body, .47 ; head and thorax, .36; abdomen, .11 inch. 



New Jersey, (Coll. Ent. Soc. Phil.). 



This very aberrant species connects this genus with Ceratocolus 

 vexhillatus of Europe, by its very long thorax, and shortened abdomen; 

 and rather than place it in Ceratocolus, I prefer to consider it as a 

 Crabro, but forming a distinct section of the genus as indicated above, 

 as it does not differ essentially in the ueuratiou of the wings, nor in 

 the form of the head as seen from above. It differs in the elongated 

 front, and the structure of the fore femora, and is much smaller than 

 usual; and in this respect, and in the want of any yellow markings on 

 the thorax, except the tubercle, and its coarsely punctured body, will 

 be easily recognized. 



Crabro bellus, Cresson. 



C. bellus, Cresson, Proc. iv. p. 481. (1865). 

 Colorado Territory, (Coll. Ent. Soc. Phil.). 



Crabro atrifrons. Cresson. 



C. atrifrons, Cresson, Proc. iv. p. 483. (1865). 



Colorado Territory, (Coll. Ent. Soc. Phil). 



