504 PROCEEDINGS OF THE NATIONAL MUSEUM. tol. 63. 



Propodeum extending beyond base of hind coxae; abdomen long and slender, 

 strongly compressed beyond second tergite, the latter very much longer 

 (two to six times) than wide and with its sides subparallel or weakly diver- 

 gent; angle of radius right or obtuse, far removed from cubitus, the inter- 

 cubitus much longer than that portion of cubitus between it and recurrent, 

 the latter occasionally interstitial; ovipositor most frequently long and 

 straight Cremastini. 



None of the species available for study agree in all particulars 

 with any of the genera proposed by Szepligeti, nor with Celor, Seme- 

 now, although a number of the species of Cremastus might with pro- 

 priety be referred to certain of these genera. 



DemopJiorus Thomson seems not to occur in the North American 

 fauna. It should bo remarked, however, that certain species allied 

 to the genotype of Zaleptopygus Viereck, here considered a subgenus 

 of Cremastus, have the upper portion of the intercubitus shghtly 

 thickened and angulate, and occasionally a wing is found in which 

 the second intercubitus is represented by a stump of a vein arising 

 from this angle. 



One new genus is described below for the reception of Cresson's 

 Porizon stlgmaterus. 



KEY TO NORTH AMERICAN GENERA OF CREMASTINI. 



Thorax very long and slender, nearly cylindrical; propodeum with areola very 

 long and petiolar area very short, areola usually much longer than petiolar 

 area; thorax and head clothed with a very dense, short, pubescence, which 

 gives a silky lustre; stigma narrow, radius arising far beyond the middle; 

 radial cell very long and narrow, its lower angle very broadly obtuse; second 

 ah-v^issa of radius curving gradually outward, then ehargly forward; eyes 

 slightly convergent towards the naiTow, strongly convex clypeus; spiracle 

 of first tergite at or not far beyond middle; orbits immaculate except for an 

 obscure brownish mark at level of antennae Pseudcriplerniis Viereck. 



Thorax not subcyUndrical, much stouter in front or short and thick; petiolar area 

 seldom shorter than areola, usually much longer; thorax and head with 

 different vestiture; stigma, if narrow, with radius arising at about middle; 

 eyes parallel or slightly divergent toward clypeus; spiracle of first tergite far 

 beyond middle; orbits more or less distinctly pale marked or the head is 

 entirely pale 1. 



1. Palpi very long, the maxillary palpi reaching to middle coxae; abdomen weakly 



compressed Dolichoselcphus Aslimead. 



Palpi normal; abdomen usually strongly compressed 2. 



2. Head small, scarcely as wide as thorax; eyes large, parallel within; face much 



narrower than eye is long; malar space very short; lateral ocelli distant from 

 the eyes by much less than their own diameter; stigma very broad, the radius 

 originating in the middle, its first abscissa strongly curved; nervulus ante- 



furcal (male unknown) Neocremastus, new genus. 



Head at least as wideas thorax, face broad, malar space not especially short; lateral 

 ocelli distant from the eyes by at least their own diameter (in some males 

 the eyes and ocelli are very large, the malar space, the ocell-ocular line, and 

 the width of the face being much reduced); stigma various, if broad, with 

 the radius usually arising beyond the middle, first radial abscissa not strongly 

 curved, nervulus interstitial or postf ureal, very rarely distinctly an tef ur- 

 eal Cremastus Gravenhorst. 



