MONOGRAPH OF THE NORTH AMERICAN PROCTOTRYPID.E. 39 



Abdoiueu entirely rufous. \\'iuj;.s salty white, the stigmti and uer 

 vures hyaline. 



Habitat. — Yuma, Ariz., Montana, Texas, and Virginia. 



Types in Coll. Ashmead, National Museum, and American Entomo- 

 logical Society. 



The males of this species are common, the females rare. 



Both sexes were taken together under stones near an ant's nest, by 

 Mr. Pergande, August ~), 1885, at Occoquan Falls, Virginia, and a 

 single 9 w:as taken from the nest of Formica obscuripes at Helena, 

 Mont., by Titus Ulke. 



Isobrachium montaiium s[> nov. 



9 . — Length, 5 '"">. Head oblong, twice as long as wide, piceous black, 

 punctate, very faintly pubescent, l^^yes and ocelli wanting. Mandi- 

 bles rufous ending in 2 black teeth. Antennje 13-jointed, brownish 

 yellow, the scape less than half the length of the flagellum; pedicel 

 longer than the first funiclar joint; Hagellar joints, except the first and 

 last, a little wider than long, the last joint f>blong. Abdomen much 

 longer than the hea<l and thorax united, i)ale brownish-yellow. 



S . — Length, 4 """. I lead and thorax black, the collar pale ; antennae, 

 mandibles, legs, and abdomen brownish yellow; wings salty white. 

 The thorax is smooth, impunctured, while the middle grooves of the 

 mesonotum are only slightly indicated anteriorly. Metathorax long, 

 smooth, impuuctate, the central carina abbreviated. Abdomen longer 

 than the head and thorax together. 



Habitat. — Montana and Arizona. 



Types in Coll. Ashmead. ' 



The 9 of this species was taken from the nests of Formica rtifihar- 

 bis by H. G. Hubbard at Helena, Mont., while the male, here associated 

 with it, was obtained from a collection in Arizona; still the structure 

 and color of the abdomen are so similar that there is no doubt left in 

 my mind that thej^ are sexes of the same species. 



Isobrachium florideinuni Asluii. 

 Ent. Am., iii, p. 7ti; Cri-ss. .Syn. Hyui., p. 247. 



i . — Length, 2.5 """. Black, suboi)a(pu', finely punctate and sparsely 

 covered with a whitish pubescence. Head oblong, closely punctate; 

 eyes jiubescent, mandibles long, crossing each other at tips. Antenufe 

 13-jointed, ferruginous, covered with a dense pubescence ; scape clavate, 

 about half the length of the head; pedicel not longer than wide at 

 tip, narrowed at base; first flagellar joint a little shorter, the joints be- 

 yond longer. Prothorax trapezoidal, longer than wide across the base; 

 mesonotum very short without furrows; scutellum with a transverse 

 impressed line at base; metathorax qmulrate with numerous longitu- 

 dinal raised lines at base. Wings fusco-hyaline, the nervures brown j 



