Fossorial ITymenoptcra of North America. 89 



Length of body, .04; head and thorax, .33; abdomen, .31 inch. 



Conn., (Norton). 



Differs from C. singularis in its much narrower and slenderer body, 

 narrower head, larger palpi, with mandibles grooved towards insertion 

 in the middle area; in the wholly black meso- thorax, except the yellow 

 tubercle, and in the abdomen having an additional pair of fasciae. The 

 tip of the abdomen is scarcely one-half as large, of different proportions, 

 being longer and narrower than in C. singularis, while the abdomen is 

 much flattened above, where in C. singularis it is much more convex. 



Crabro trapezoideus, n. sp. 



% . Closely allied in some respects to C. singularis, connecting that 

 species with 0. 6-maculatus. Head narrowing rapidly behind, trape- 

 zoidal. Surface puncto-striated; eyes prominent, front deeply exca- 

 vated; antennal groove well marked; orbits silvery; antennae very 

 long and slender, scape long, entirely yellow, joints of flagellum 

 piceous black, paler at base; middle joint subdentate, fourth joint 

 thickened and flexed beneath, terminal joint long obconic; ocelli pro- 

 minent; clypeus black, with silvery pubescence; mandibles yellow, 

 black at base and tip. Thorax pilose ; on prothorax two broad fasciae, 

 tubercle yellow, ocellated with black. 



Two geminate lunate spcts on the meso-scutum. Propodeum covered 

 with a net-work of confluent rugae, enclosure obsolete ; mesial furrow 

 deep and distinct; wings a little clouded with the usual violaceous re- 

 flections. Fore legs entirely yellow; femora dilated behind, with a 

 sharp spine near the middle, with a fringe of hairs; middle legs yel- 

 low, femora and tibiae slightly shaded with fuscous brown behind ; 

 hind femora brown black beneath, above testaceous ; middle and hind 

 tarsi with tip of basal and four terminal joints dark, glaucous brown. 

 Abdomeu high, ovate, subpedunculate, shorter than head and thorax 

 together; on second ring are two ovate fasciae closely approximate; 

 the other four decreasing in size, becoming more pointed above and 

 more lateral. 



Length of body, .48 ; head and thorax, .25 , abdomen, .23 inch. 



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



In the subpedunculated abdomen this species approaches C. Q-macu- 

 tatus, but differs totally in the characters exhibited in the head and 

 thorax, and in the coloration of the abdomen. From C. quadriceps $ , 

 it maybe known by its head being broader behind, being more trapezoi- 

 dal than angular when seen from above, and also by the pale yellow 

 legs. 



PROCEEDINGS ENT. SOC. PHILAD. HAY, 1866. 



