100 S. A. ROHWER. 



This species seems to be very close to Passalcecus scudderi 

 Ckll. (Bull. Mus. Comp. Zoo., p. 46, vol. L, No. 2, 1906), being 

 easily known by its larger size, and having a more transverse 

 head. The general habitus of P. fasciatus is very similar to 

 P. mandibular is Cresson, a recent species found at Florissant. 



The presence of the spurious nervure on the second trans- 

 verse cubitus led me at first to think that there was a petiolate 

 second cubital cell, and I could not place the specimen in any 

 genus. On examining a specimen of Passalascus mandibular is, 

 there was no doubt in my mind that the fossil was a Passala?cus. 

 The shape of the radial, and the basal nervures are exactly as 

 in this genus. 



It seems strange that the only two fossil Pemphredonids 

 described should have the abdomen banded with pale bands. 

 I have gone through a number of descriptions of Pemphredonids 

 from all parts of the world ; but in none of them was the abdo- 

 men banded with pale bands. It may be possible that if we 

 had a recent specimen this insect would belong to a different 

 genus. 



Passaloecus mandibularis Cresson 



I have two females of this species from Florissant, Colorado, 

 collected by Prof. T. D. A. Cockerell; one June 30, 1907, the 

 other July 21, 1906 "on stump of Pinus scopulorum probably 

 nesting." The intermediate tibiae of one of these is black. 

 A male from North Boulder Creek, Boulder Co., Colorado, 

 August 21, 190S, on foliage of Heracleum lanatum, Canadian 

 Life Zone (S. A. Rohwer). 



Pa,ssal<ecus relativus Fox. 



Female. — Length 5.5 mm. Head finely closely punctured, more 

 finely so on the front. Inner eye margins narrowing but little towards 

 the clypeus. Clypeus in the middle produced into a low, broad, trun- 

 cate process the angles of which are slightly dentate. Frontal im- 

 pressed line distinct, but not strong; ocelli placed in shallow pits, the 

 distance between the posterior pair slightly greater than the distance 

 between one of them and the nearest eye margin. Dorsulum finely 

 closely punctured, the furrows distinct but not strong; scutellum 

 punctured like the dorsulum, not impressed; mesopleurse finely punc- 

 tured, the suture strongly foveolate. Metapleurae reticulate, at the 

 sides not so coarsely so; the base of the metapleurte finely, transversely 



