Fossorial Tlymcnnptcra of North America. 375 



BCntellum dark. On thoracoabdominal ring the mesial furrow widens 

 towards the base, granulated, while the enclosure is highly polished on 

 each side, with no punctures or lines. Beneath smooth. Legs smooth, 

 femora black, fore and middle broadly tipped with yellow, posterior 

 pair entirely black, tibiae yellow; tarsi yellow on the basal joint, grow- 

 ing more ferruginous towards the ungues. 



Abdomen hardly longer than the thorax alone, narrow, as broad as 

 high, cylindrical, being very convex above, each ring continuously 

 banded on the hinder edge with obscure testaceous, tip acute, though 

 not so much so as in most of the species. 



Length of body, .28; head and thorax together, .18; abdomen, .10 

 inch. 



Cambridge, Mass., on flowers. (Harris Coll.). New York, (Angus, 

 Coll. Ent, Soc. Phil.). 



This species will be easily known by its smooth thoraco-abdominal 

 segment, the obscure testaceous hinder margin of the abdominal seg- 

 ments, and by its prothorax being continuously banded above, not 

 being interrupted by the mesial notch. The tubercle is not colored 

 yellow, this together with the large yellow scutellum and its small size 

 will readily distinguish this interesting species. 



One of the specimens still had the pellicle of the sub-imago — for 

 such a stage exists in some of the Hymenoptera as well as in 

 the Neuroptera — still attached to the abdomen, and the wings had not 

 acquired their elasticity, as the fluids had not evaporated from their 

 surface when the insect was taken. This specimen in the manifest im- 

 maturity of the abdominal region as compared with the anterior regions 

 of the body, is interesting, as affording an additional proof of the pro- 

 gressive development of the body from the head backwards. This fact 

 I have observed in the development of the genus Bombus. The parts 

 remotest from the head, and the terminal portions of the appendages 

 are the last to come to maturity. Also in this same specimen the tarsi 

 are still immature, while the tibia) are mature, having obtained their 

 usual hues and density of the outer crust. 



Elepharipus scutellatus. 



C. scutellatus, Say, Long's Second Exp. App. p. 341. (1824). 



Smith, Cat. Ilym. Br. Mus. iv. p. 418. (1856). 



% . Head as described in B. impressifrons, but more transversely 



elliptical, and narrowing more behind; vertex and front the same; cly- 



peal region narrower and clypeus proportionally longer, well carinated; 



mandibles piceo-fuscous ; equally bidentate, darker at the upper edge 



JS 



