12 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.63. 



complete; lateral lobes coarsely shagreened along their inner margin; 

 posterior margin of mesonotum with long hairs projecting over the 

 scutellar fovea; scutelhim transverse, roughened, with a large central 

 space densely covered with short whitish hairs, lateral margins of 

 scutellum very high and sharp, projecting above the surface of the 

 scutellum; propodeum rather finely roughened, densely covered with 

 erect long white hair; median carinae close together and parallel; 

 first tergite as wide as long, slightly narrowed anteriorly, roughened 

 and covered with erect white hair on each side of the median area; 

 median area well defined, widened flask-like anteriorly, much longer 

 than wide; abdomen obovate, a little over twice as long as wide, 

 wider than the thorax, as long as the head and thorax united ; second 

 tergite two-thirds as wide as long, three-eighths as wide at base as 

 at apex, without sculpture of any sort; basal foveae deep, not espe- 

 cially large, as long as the first tergite, pubescent; tergites three to six 

 finely shagreened, united three-tenths as long as the second, the 

 third a little the longest; wings brownish, extending half the length 

 of the second tergite past the apex of the abdomen. Black; antenna 

 and legs (except last six joints of the former and the coxae) brown- 

 ish yellow, shining; antennal club brown, coxae black. 



Male. — Length 3 mm. Pedicel one and one-half times as long as 

 wide; as long and as wide as joints three and four; joint three elon- 

 gate and more or less triangular; four cylindrical, slightly widened 

 below at apex ; five cylindrical, a little longer than wide, as wide as 

 four at apex; joints six to nine as wide as four, becoming gradually 

 longer distall}"; ten very long and acute apically, nearly as long as 

 eight and nine united, three times as long as wide; abdomen sculp- 

 tured as in the female, spatulate, a little over twice as long as wide, 

 as long as the head and thorax united; tergites three to seven finely 

 shagreened, thickly pubescent, united one-third as long as the second; 

 wings extending the length of the second tergite past the apex of the 

 abdomen. Coloration as in the female; flagellum, including the ped- 

 icel, usually brownish, sometimes yellow. 



Type locality. — Ottawa, Canada. 



Other localities. — Greeley, Colorado; Algona, Iowa; Texas; Michigan. 



Type. — One of Provancher's male paratypes is in the National 

 Museum (Cat. No. 25427). The types of I. nigriclavus are also in the 

 National Collection (Cat. No. 2306). 



Besides the types mentioned above the National Collection has a 

 number of specimens from the Agricultural College in Michigan. Sev- 

 eral of these specimens arc recorded as having been reared March 10, 

 1887, from a gall on willow. The others bear only the labels, "June 

 3, 1887," and "Ag. Coll. Mich." 



