342 PROCEEDINGS OF THE NATIONAL. MUSEUM vol.88 



Distntution. — In addition to the localities in the type series, ma- 

 terial has been secured from Arizona, Iowa, Kansas, Missouri, Mon- 

 tana, Utah, Texas. 



SPILOCHALCIS DELUMBIS (Cresson) 



FiGUKES 9, o; 14, n 



Smicra delumbis Cresson, Trans. Amer. Ent. Soc, vol. 4. pp. 36, 40, 1872. — 

 AsHMEAD, ibid., vol. 12, p. x, 1885. — Howard, U. S. Dept. Agr. Bur, Ent. 

 Bull. 5, p. 34, 1885. — Cresson, Synopsis of the families and genera of the- 

 Hymenoptera of America north of Mexico, p. 233, 1887.— Dat.t.a Toeke,. 

 Catalogus hymenopterorum, vol. 5, p. 375, 1898. — Schmiedeknecht, Genera 

 insectorum, fasc. 97, p. 34, 1909. 



Spilochalcis delumbis (Cresson) Viekeck, Trans. Amer. Ent. Soc, vol. 32, p. 184, 

 1906.— Chamberlin, Proc. Ent. Soc. Washington, vol. 85, p. 101, 1933. 



Spilochalcis delumbis is separable from S. side only by critical 

 characters. Each of these species is, furthermore, quite variable, but 

 as the variation from one to the other is not quite continuous, they 

 had best be retained as different species. As I have seen over a thou- 

 sand specimens of these two species from a great many localities, the 

 discontinuity between them probably will not disappear when more 

 material is secured. The males are usually readily separable, but the 

 females are to be distinguished only with difficulty. 



The male of this species always has the antennae inserted on a 

 level with the ventral margins of the compound eyes; the pedicel is 

 small and cup-shaped and considerably narrower than the flagellum. 

 The vertex is subacute rather than broadly rounded. Only an occa- 

 sional male specimen has an angular color band dorsad of the clypeus; 

 the interocular space is wide and the compound eyes are narrow. In 

 the female, the vertex is subacute, the interocular space is wide and 

 the eyes narrow, and the mesal projection of the eighth sternite is 

 acute; this last character is often difficult to see, as the tergites of 

 the anterior abdominal segments usually project ventrad so as to 

 conceal the eighth sternite. 



Desciiption. — Male: 4-5 mm. Antennae inserted on a level with 

 ventral margins of compound eyes, scape (fig. 9, o) with apex reach- 

 ing level of dorsal margin of anterior ocellus, pedicel narrower than 

 flagellum, three-quarters length of segment 4, ring segment one- 

 quarter length of 4, 5 slightly longer than 4, segments 5 to 12 variable. . 

 usually equal in length, 12 often appearing subdivided, 13 minute; 

 scrobe cavity shallow, margin usually completely acarinate, some- 

 times with obscure lateral carinae, glabrous areas lacking; frons 

 irregularly and very minutely reticulated and shagreened, setae short, 

 rather dense over most of surface; width of malar space one-half 

 height of compound eye; combined widths of compound eyes one- 

 fifth less than interocular space ; left mandible with two teeth, ventral 



