Fossorial Bymenoptera of North America. 403 



Length of the body, .86; head and thorax, .22; abdomen, .14 inch. 



Mass., (Sanborn). 



Easily recognized by its unusually large size, its long pedicel, even 

 when compared with P. ni'yer, in which species it is remarkably long; 

 by its unusually deep golden pubescence, not only on the front, but on 

 the orbits behind the eyes, and on the flanks of the thorax ; by the 

 bbod-red hind edge of the three basal abdominal rings, and by the 

 dark tibiae and pale fuscous tarsi, the well marked rugae, six on each 

 side of the mesial furrow, which is interrupted by three transverse 

 rugae, of which the first is the largest. 



DESIDER.VTl'jr. 



Psen mellipes. Say. 



Pscn mdlipcs, Say, Jour. Bost. Soc. Nat. Hist., i. p. 369. (1836). 



MIMESA Shuck. 

 llimcsa, Shuck., Foss. Hym. p. 2S8. (1837). 

 Head very transverse, scarcely one-third as long as broad, a little 

 wider than the thorax, vertex elevated, very convex, ocelli arranged 

 in an equilateral, rather low triangle ; eyes large and prominent, more so 

 than in Psen : the front contracts much more in the middle ; beino; 

 narrower above and expanding more at the clypeus, which is oval 

 elliptic, surface convex, rounding in front, and proportionally larger 

 than in Pscn; with a conspicuous interantennal prominence. Antenna) 

 clavate, scape stout and thick, flagellum clavate, rarely filiform, joints 

 sometimes subdenticulated beneath towards the base. Thorax much 

 as in Psen, but more pubescent, with the propodeum more produced 

 posteriorly ; enclosure broader, triangular ; posteriorly the propodeum 

 is much produced behind it. The sculpturing varies very much, there 

 are more usually 4 rugae on each side of the mesial furrow, which are 

 more or less distinct, and posteriorly form lines radiating towards a 

 net-work of irregular rugae. Legs much longer and joints slenderer; 

 the pterostigma is larger and more distinct than in Psen ; the 2d sub- 

 costal cell also is much larger and more broadly trapezoidal, and 

 the 2d submedian cell is much larger, and the outer side Btraighter, 

 not curved as in Pscn. 



The abdomen varies much in length, in some species being twice 

 as long as the rest of the body; pedicel from one-half to two-thirds as 

 long as the abdomen is wide, usually smooth and polished, grooved 

 laterally, body of the abdomen ovate, or more usually ovate-lanceolate; 

 rings not coarctate; sutures slightly impressed, tips pointed, hirsute, 

 with an upturned penis. 



