174 PASSALCECUS CORNIGERA. 



Diodontus gracilis, Curtis, Brit. Ent. xi. 496. 

 Passaloecus gracilis, Shuck. Fuss. Hym. 190. 2. 



Dahlb. Hym. Europ. 242. 142. 



Wesm. Hym. Foss. Belg. 121. 1. 



Female. Length 2f lines. — Black and shining ; the head deli- 

 cately punctured; the clypeus marginate and obsoletely tri- 

 dentate ; the scape in front, and a broad stripe on the mandibles, 

 yellow ; palpi pale. Thorax : the mesothorax closely punctured; 

 "the scutellum very delicately so ; the metathorax rugose and 

 shining ; the wings hyaline and iridescent ; the tegulae piceous ; 

 the anterior tarsi, and the knees and tarsi of the intermediate pair, 

 pale ferruginous ; the base of the posterior tibiae pale yellow. 



The Male only differs in having the face silvery, and the pale 

 parts of the legs yellow. 



3. Passaloecus cornigera. 



P. atra ; corniculo inter antennas porrecto ( $ ), obsoleto ( $ ). 



Passaloecus cornigera, Shuck. Foss. Hym. 191. 3. 

 Dahlb. Hym. Europ. i. 245. 145. 



Female. Length 2-3 lines.— Black ; the head, and thorax on 



the disk, verv delicately punctured ; the metathorax coarsely 



rugose; the abdomen smooth, shining, and impunctate. An 



erect acute spine in the centre of the face, and an impressed 



line above it, extending to the anterior stemma; the clypeus 



tridentate, the central tooth largest; the scape in front and 



the tips of the mandibles rufescent ; sometimes only the base 



and apex of the scape rufescent. Thorax : the epaulets of the 



tegulae consute, a slight scratch parallel with their middle, and 



a consute line on each side near the middle, extending from 



the base to the apex, within which, at the base, there are two 



slight, abbreviated, slightlv elevated lines. The tubercles white ; 



the wings hyaline and iridescent ; the tegulse rufo-testaceous ; 



the anterior and intermediate tibia? and tarsi, the tips of their 



femora, and the base of the posterior tibiae, fulvous ; the apex 



of the posterior tibiae sometimes also fulvous ; a dark stain in 



the middle of the intermediate tibiae. Abdomen : the margins of 



the three basal segments slightly constricted. 



The Male has the spine on the face obsolete ; the clypeus with 



a silvery pubescence ; those parts of the legs which are fulvous 



in the female are luteous. 



This and the preceding species are plentiful in the London 

 district, and apparently widely distributed. 



