AMKRICAN HYMENOPTERA. ioo 



cellule — a slightly less distance than the front of the cellule; the second recur- 

 rent nervure is roundly curved backwards on the front three-fourths, the poste- 

 rior part is straight and slightly oblique. 9 • Length 8 mm. 



Front and vertex closely, distinctly [)unctured, the puncturation weaker on 

 the outerside of the vertex ; there is a narrow, but distinct keel down the lower 

 half of the front; the pubescence is longisb, not very close and silvery. Meso- 

 notura somewhat strongly and closely punctured in the middle, the sides almost 

 smooth. Scutellum almost smooth, the postscutellum shagreened. Propleura' 

 and mesopleurse shagreened ; the metapleurse somewhat widely reticulated. 

 Legs covered thickly with white pubescence; the hind tibi* are distinctly spi- 

 nose behind; the calcaria white; the four anterior tarsi are tinged with testa- 

 ceous. Underside of flagellum fuscous. Pygidium depressed somewhat, covered 

 with large, clearly separated punctures, not acute at apex, about one-fourth 

 longer than it is wide at the base; it is not distinctly margined laterally. 



Berkeley Co., Colorado ; June. 



Except that the pygidium can hardly he called "acute at apex," 

 this species would come into Mr. Fox's Group 2 (Trans. Am. Ent. 

 Soc, XXV, 5), and in the table, on p. 2, it certainly runs near to 

 cylindricui^ and reyularis of that group. It is a Mhnem. 



Closely allied to the above is a species I have from New Mexico. 

 The main ditierences between the two may be shown thus : 



The second recurrent nervure not interstitial, broadly roundly curved in 

 front; the front with a distinct keel; the abdominal petiole not much 

 shorter than the bind femora coloradoensis. 



The second recurrent nervure interstitial, at the top straiglit, oblique, bent 

 backwards, forming a sharp angle with the rounded lower part, the 

 front without a distinct keel, the abdominal jietiole distinctly shorter 

 than the femora interstitialis. 



Psen iiiterstilialis* sp. nov. 



Face and clypeus densely covered with a silvery pubescence, the apes of the 

 latter broadly rounded. Hind ocelli separated from each other by a distinctly 

 less distance than they are from the eyes; the anterior is surrounded by a smooth 

 furrow which goes down the front for a short distance; the punctuation is weak, 

 not very distinct ; the pubescence silvery, moderately long and dense. Prothorax 

 and mesothorax almost smooth; the metanotum and metapleurse at the base 

 reticulated ; the area large, not narrowed to a point at the apex; the sides and 

 apex smooth, the centre with four or five stout, oblique keels. Legs densely 

 covered with silvery pubescence, all the tarsi rufo-testaceous, the calcaria white; 

 the tibife weakly spinose. Abdominal petiole stout, not dilated at the apex ; the 

 top in the centre raised, the sides furrowed near the base. % . Length b mm. 



The first recurrent nervure is received the length of the second abscissa of the 

 radius from the base of the cellule. Pygidium smooth, triangular. The antenna- 

 are as long as the bead and thorax united ; the flagellum is entirely brown. The 

 base of the metapleura^ is almost smooth, the rest distinctly, somewhat strongly 

 obliquely striated. 



TKAN6. AM. ENT. hOC . XXXIV. (30) JULY, 1908. 



