86 C. p. GILLETTE. 



Group I (AntennfB of female 13-jointed). 



The females of this group may be separated as follows : 



A. Thorax entirely black. 



B. Abdomen not distinctly longer than broad atra n. sp. 



BB. Abdomen distinctly longer than broad (liinoi*|>liii!« O. S. 



AA. Thorax and head almost entirely rufous bicolor Ash. 



AAA. Thorax above black. 



B. Mesonotura with long, transverse wrinkles, which are very distinct, some- 

 what shining tliiiiorplius O. S. 



BB. Mesonotum indistinctly transversely wrinkled and opaque. 



C. Antennpe not reaching the scutellum medullar Ash. 



CC. Autennse reaching the scutellum lignicola O. S 



Synergiis atra n. sp. 



Female. — Color black, with face beneath the eyes, antennse and legs somewhat 

 yellowish. Head sharply and finely striated beneath the antennse, vertex and 

 occiput microscopically sculptured and with scattered, broad punctures; antennae 

 13-,iointed, the last joint once and a half the length of the preceding and con- 

 spicuou.sly black, third joint once and a half the length of the fourth ; coloi", 

 except the last joint, yellow ; would reach to about the middle of the abdomen. 

 Thorax deep black, opaque, pronotum rather coarsely transversely rugose, espe- 

 cially posteriorly, parapsidal grooves distinct, nearly parallel, fovese of scutellum 

 small, but shining, disc of scutellum coarsely rugose, collar coarsely rugoso-punc- 

 tate, mesopleurje entirely aciculated. Abdomen black, as broad as long, ventral 

 valve projecting, sides of second segment not punctured posteriorly. Legs with 

 tibiae and tarsi of two anterior pairs yellowish, remaining portions, except at the 

 joints, blackish. Wings with marginal cell closed, areolet very small and indis- 

 tinct, tegula' dark brown. Length 2 mm. 



Utile. — Differs from the female by having a smaller abdomen, and in liaving 

 the antenna 14-joiuted, with the third joint excised and fully as long as the two 

 following together. 



Described from four females and three males bred from unknown 

 galls by the writer, at Lansing, Mich., and two females bred from 

 galls of Holcasjm ruhem Gill, taken at Manitou, Colorado. 



Without close examination this species would be taken for small 

 individuals of Siiiirrgii>< mmpanida O. S., but it is readily separated 

 from that species by the coarser sculpturing of the mesonotum, the 

 18-jointed antennse of the female, and the nuieh longer third joint 

 as com{)ared with the foiu'th. 



Synergus diinorpliu^i O. S. 



^ynerifUH dimorphii.s O. S., Proc. Ent. Soc. Phila. iv, 1865, p. .376, n. 5, ^ %. 



Rynerijm dimurphns Cresson, Synop. Hym. Amer., 1887, p. 180. 



Synergiis dimorplms De Dalle Torre, Cat. Hym. ii. 1893, p. 110. 



"Female. — 0.12-0.13 long. Head black, except the face, which is browni.sh red 



mixed with black, below the autennse ; mandibles (except their tip, which is 



black) and more or less spac^e near their roots on cheeks, yellowish ; the brownish 



coloring of the face extends above the autenute in the shape of a narrow stripe 



