180 DIPTERA OF NORTH AMERICA. ' [PART II. 



Face broad for a male, though a little narrower downward ; the 

 dust is of about the same color as the rest of the body, usually, 

 however, somewhat paler. Palpi black, of middle size. The 

 third joint of the antennas small, kidney-shaped, with an entirely 

 apical arista. Front quite opaque on account of its thick dust. 

 The metallic-green ground-color of the upper side of the thorax 

 becomes more visible only when seen from behind. Scutellum and 

 abdomen less thickly covered with dust than the thorax, so that 

 their metallic ground-color becomes more apparent in most direc- 

 tions. The hair upon the abdomen appears, in a reflected light, 

 of a pale-brownish color. Coxae a,nd femora black, without a dis- 

 tinct green lustre, the second joint of the fore coxae, the extreme 

 tip of all femora, all the tibia? and all the tarsi as far as the tip of 

 the first joint, yellow ; the end of the tarsi dark brown. The hair 

 and bristles upon the feet very short everywhere, the bristles also 

 very scarce ; the pul villi of the fore tarsi rather small. Cilia of 

 the tegulaa pale. Wings somewhat grayish, with a rather protrud- 

 ing anal angle and of more uniform breadth than in most of the 

 other species ; the fore margin of the wings shows a strong black 

 thickening, which commences abruptly at the end of the first lon- 

 gitudinal vein, becomes then gradually thinner and disappears 

 already before the end of the second longitudinal vein ; the last 

 segment of the fourth longitudinal vein is not inflected at all, 

 parallel with the third and ends rather exactly in the extreme tip 

 of the wing ; the posterior transverse vein is almost at an equal 

 distance from the extreme root and from the tip of the wing. 



Bab. Florida. 



Female. It resembles the male very much, only the dust upon 

 the whole body is more thick and the green ground-color of the 

 abdomen less bright. The face is not very broad for a female ; 

 its covering of thick dust has the same color as that on the rest 

 of the body ; although the usual transverse swelling lies somewhat 

 below the middle of the face, it is considerably higher than in the 

 females of all the other species known to me, so that the face is 

 divided by it into two almost equal parts. The wings have the 

 same shape of equal breadth as in the male, show however no trace 

 of a thickening on the fore margin. 



Hab. Maryland. (Osten-Sacken.) 



