14 PROCEEDINGS OF THE NATIONAL MrSEUM, vol. G3. 



notum finely shagreened on anterior half, polished otherwise; riotauli 

 nearly parallel, deep and wide posteriorly, not quite reaching the 

 pronotum; median lobe broadly truncate posteriorly; scutellum ele- 

 vated into a transverse ridge, sharply and highly margined laterally, 

 with a tuft of short white hairs on its posterior face, covered all over 

 with long white hairs; petiole a little wider than long, fluted, the 

 median area longer than wide, with a central carina; abdomen ellip- 

 tical, a little over twice as long as wide, distinctly longer than the 

 head and thorax united ; second tergite as wide as long, without stri- 

 ations basally, narrowed anteriorly, the sides straight; foveae deep 

 but not especially large; tergites three to six finely shagreened, about 

 equally long, united four-fifths as long as the second; six a little 

 wider than long, rounded apically, with scattered pubescence; wings 

 slightly tinged with brown, scarcely reaching beyond the apex of the 

 abdomen. Black; legs and scape yellow; the hind coxae and joints 

 two to five of the antenna touched with brown; club-joints fuscous. 



Male. — Length, 2.20 mm. Pedicel less than twice as long as wide, 

 as wide as joints three and four, a little longer than three; four cylin- 

 drical, as long as two and three united; joints five to nine a little longer 

 than wide; ten conical, acute at apex, longer than four; abdomen wider 

 than the thorax, a little over twice as long as wide, rounded apically, 

 longer than the head and thorax united; segments three to seven 

 finely shagreened, about equal in length, the last shorter, rounded 

 apically; three to seven united a little over half as long as the second. 

 Flagellum, including the pedicel, light brown in color. 



Type locality. — Arlington, Virginia. 



Allotype locality. — Washington, District of Columbia. 



Othe?' ZocaZ-i^es.— Jacksonville, Flordia, and St. Louis, Missouri. 



Type. — Cat. No. 2277. U.S.N.M, Female from Arlington, Virginia, 

 selected as type and male from Washington as allotype. Other 

 specimens considered paratypes. 



Redescribed from the type series, three females and one male, in the 

 National Museum at Washington. The Missouri specimen was reared 

 from acorns infested with Balaninus nasicus and Blastohasis glandul- 

 ella. 



2. TRICHACIS RUBICOLA Ashmead. 



Trichacis rubicola Ashmead, Bull. 45, U. S. Nat. Mus., 1893, p. 296. — Brues, 

 Bull. 22, Conn. Geol. Nat. Hist. Sur., 1916 (1917), p. 534. 



Trichacis arizonensis Ashmead, Bull. 45, U. S. Nat. Mus., 1893, p. 296. (Not 

 Isorhombus arizonensis Ashmead, p. 277.) 



Trichacis brunneipes Ashmead, Bull. 45, U. S. Nat. Mus., 1893, p. 296. 



/^emaZ^.— Length 1.60 mm. Head twice as wide as long, as wide 

 as the thorax, narrow behind the eyes; occiput strongl}^ and regularly 

 transversely striate, separated from the vertex by a sharp carina; 



