6 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



reddish ; third joint a little shorter than the first two together, except 

 the base, black. Tliorax coppery-shining, the pnrj^lish stripes of the 

 dorsum sub-opaque, pile of the dorsum sub-aureous, of the pleurae white. 

 Scutellum coppery shining, and sub-aureous pubescent. Color of the 

 abdomen bronze-greenish, near the lateral margin in the male more obso- 

 letely, in the female more distinctly, coppery, margin of the last segment 

 nearly luteous. Abdomen subaureous pubescent, on the sides near the 

 base with white pile, near the tip with black pile. Legs saturate testa- 

 ceous or fuscous red; basal half of the femora always for the great 

 part fuscous black. Tarsi sometimes fuscous. Wings cinereous hya- 

 line, transverse veins and the anastomoses broadly clouded with fus- 

 cous black. 



Translation from original, compared with the types in the Museum of 

 •Comparative Zoology. 



Microdon coarctatus. 



Microdon coarctatus Loew, Centur., v, 47. 



Habitat. — District of Columbia (Lw.) !. 



S , 9 . Slender, steel green, moderately shining, eyes subnude, front 

 and face narrow, ocelli remote from the vertex, antennse short, black, 

 margin of the second abdominal segment tumid. Length of body 7 to 

 gmm^ of wings 6™'". 



Slender, steel green, moderately shining, white/ pubescent. Front of 

 equal width, in the female a little broader than in the male, ocelli re- 

 mote from the v^ertex. Antennse black, short, third joint a little longer 

 than the first two together. Dorsum of thorax bronze green, very lightly 

 punctulate and transversely aciculate, with four obscure coppery stripes. 

 Scutellum greenish black, the apex emarginate and on each side pro- 

 vided with a black tooth. Abdomen in the male cylindrical, obtuse, in 

 the female acute ; second segment a little broader than the following, 

 the disk depressed, with the lateral margins somewhat tumid. Wings 

 cinereous hyaline, the transverse veins clouded with black, posterior 

 angle of the first posterior and discal cells rounded, very shortly ap- 

 pendiculate. 



Translation from the original, compared with the two type specimens 

 in The Museum of Comparative Zoology. 



Microdon tristis. (Plate I, figs. 3, 3a.) 



Microdon tristis Loew, Ceutur., v, 45. 



Microdon vothurnatum Bigot, Ann. Soc. Ent. Fr., 1883, 320 (var.). 



Habitat. — Virginia, New York, and northward as far as the Mac- 

 kenzie River (O. S.), Connecticut, Oregon!. 



$ . Black, pallidly pilose, the antennae long and fuscous black, front 

 very broad, scutellum bidentate, abdomen oblong-ovate, the penulti- 

 mate segment subequal to the two preceding. Length of body 9™"', of 

 the wings G""". 



Head bronze black, clothed with yellowish white pile, front very 

 broad, of equal width. Antennse elongate, black-fuscous, first joint 



