184 DIPTERA OF NORTH AMERICA. [PART II. 



Both sexes resemble each other very much. Metallic-green, 

 shining. The eyes of the male meet almost completely, so that 

 the face appears small, linear ; in the female it is broader and has 

 the usual transverse swelling far below its middle. The dust upon 

 it is white in both sexes. The palpi are rather small and covered 

 with whitish dust so as to conceal the ground-color, which appears 

 to be more yellowish than blackish. The third joint of the an- 

 tennae is not large, even in the males, and but little oblique. Front 

 green, rather dull from whitish dust. The upper side of the thorax 

 has a distinct whitish dust, which however does not conceal the 

 ground-color. The black hair upon the abdomen is somewhat 

 longer than in most of the other species. The whole fore coxae, 

 the tip of the middle and hind coxae and the whole feet are yel- 

 low, even the tarsi are only slightly dusky towards the tip. Cilia 

 of the tegulae pale. Wings a little grayish, with brownish or 

 brown veins ; the posterior transverse vein lies considerably nearer 

 to the root than to the tip of the wing. 



Hab. Middle States. (Osten-Sacken.) 



12. C. picticornis, nov. sp. % . — Minutus, viridi-aeneus, modice 

 nitens, oculis infra antennas contiguis, primo antennarum articulo rufo, 

 coxis anticis pedibusque flavis. 



Small, bronze-green, moderately bright ; the eyes contiguous below the an- 

 tennse ; first joint of the antennae red ; fore coxae and the feet yellow. 

 Long. corp. 0.08. Long. al. 0.08. 



Yery small, bronze-green, moderately shining. The eyes con- 

 tiguous below the antennae. The antennae small, the first joint 

 red, the following two black, the third rather small and a little 

 oblique ; arista apical. Fore coxae and feet somewhat brownish- 

 yellow. The tip of the hind femora on the upper side and all the 

 tarsi from the tip of the first joint, brown. The hind tibiae are 

 fringed on the upper side only with a few delicate, not very con- 

 spicuous bristles, and show a dusky tinge at the tip. The color 

 of the cilia of the tegulae I cannot positively state. Wings of the 

 usual structure, grayish-hyaline with brownish-black veins ; the 

 posterior transverse vein is rather short and lies before the middle 

 of the surface of the wings. 



Hab. Illinois. (Le Baron.) 



Observation. — This description is made only after a single spe- 



