26 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



rather slender, pedunculate, shining black, and hairless except in the basal 

 portion of the left side, where the overlapping scale-like rudiments of the 

 seventh and eighth (?) segments are coated with gray dust and beset with a 

 few yellowish hairs. Appendages of the hypopygium yellow, posterior pair 

 rather short and broad, straight, fringed with yellowish hairs. Pleurae sub- 

 metallic greenish gray like the abdomen. Above the insertions of the fore 

 coxae there are four prominent white bristles on either side. Coxae black, 

 covered with yellowish white dust and with short silky white hairs on their 

 front faces. Trochanters and legs piceous, the knees lighter, the femora darker 

 towards their bases. The apices of the first to third tarsal joints black, the 

 fourth and fifth joints entirely black. Hairs on the femora white, those on 

 the tibiae and tarsi white and black, bristles on all parts of the legs black. 

 Hind tibiae slightly sv/ollen towards their tips which are black like the tips of 

 the anterior tibiae. Hind metatarsus slightly broader than the succeeding 

 joints, with a small, sharp, tooth-shaped projection on the inner side near the 

 base. Second joint of hind tarsus nearly three times as long as the first. 

 Wings hyaline, rather narrow towards the tips. Veins brown, becoming yel- 

 low proximally. Posterior cross-vein slightly bowed, about half as long as 

 the distal segment of the fifth vein. Third and fourth veins gently converg- 

 ing, running parallel with each other close to their tips and ending rather 

 close together. Tegulae and halteres yellowish white, the former with long 

 white cilia. 



Female. Length 5 mm. ; length of wing 5 mm. The coloring is the same 

 as on the male. The ovipositor is shining black, yellowish towards the tip. 

 The hind metatarsus lacks the tooth-like projection on the inner side. 



Four males and one female of this large and handsome 

 species taken at Farmingdale, N. J., July 14, 1895, (Mr. 

 C. W. Johnson). 



27. Medeterus veles Loeiv. 



Plate H, Figs. 36-38. 



This is our commonest species in the Middle States. I 

 have taken it in July on the smooth bark of trees in the 

 Chicago parks. The male has a small tooth-like projection 

 on the inner side at the base of the hind metatarsus. This 

 is not mentioned in Loew's description, which was drawn 

 from an imperfectly preserved specimen. The female of 

 M. veles resembles the male in coloration. The ovipositor, 

 which in my specimens is exserted, is yellowish brown. 

 The face is dull green below and thickly covered with gray 

 dust above the suture. 



