AMERICAN DIPTERA. 228 



Specimens have been examined from Mass., Mich., 111., Wise, 

 La., Neb., Kans., So. Dak., Colo., Wyom., Idaho, N. Mex., Calif., 

 Mexico. 



Among these specimens, which doubtless are of a single form, the 

 variations are extreme. Sometimes the tarsi are pure yellow, more 

 often sharply annulate, though at times they are dusky. A few of 

 the specimens from Wyoming have almost black feet. The legs 

 vary from reddish brown to almost white. At times the two basal 

 cells of the wings are equal, more often the second is the longer. 

 The sixth vein is more or less abbreviated at the base. The face 

 varies from white to red or fuscous, and varies also greatly in 

 breadth. The last anteunal joint is generally lanceolate, but fre- 

 quently is short. 



Platypalpus «rassireinori!<t Fitch. 

 Oscinis crassifemoris Fitch, N. Y. Reports, vol. i (1856), p. 301. 

 Platypalpus debilis Loew, Cent, iii, 37 (1861). 



Although Fitch's description of Oscinis crassifemoris is very 

 meagre, Mr. Coquillett who had the type for examination places it 

 with Platypalpus debilis Loew. 



The description of crassifemoris is given in full : 



"The thick-legged Oscinis (0. crassifemoris) is the same size with the last (0. 

 coxendix, which is 0.07 inch in length to the tip of the abdomen, and 0.10 to the 

 end of the wings), and is black, with a white head, and the thorax with a gray 

 reflection. The last joint of the antennae with its bristle is black. The legs are 

 pule yellow, the tips of the feet black. The veinlets are so near each other that 

 they are almost united. In the female the abdomen is egg shaped and polished, 

 its apex drawn out into a long, sharp-pointed ovipositor. The middle and ante- 

 rior thighs are rather short and thick, the hind ones longer and cylindrical. 



The specimens referred to this species are variable in tarsal color- 

 ing, sometimes the tarsi are yellowish, with dusky tips and some- 

 times annulate. The antennae are sometimes black, in which case 

 this species may readily be distinguished from (equalis and hastatus 

 by the smaller tibial spur and the shape of the third antennal joint. 



Massachusetts (Hough), Michigan, Idaho (Aldrich). 



Platypalpus tenellns sp. nov. (Figs. 28, 38). 

 Length 2-2.5 mm., length of wing same. — Black, head, dorsum of thorax and 

 pleurae covered with gray pollen, abdomen shining. Face silvery, rather nar- 

 row; sides of front parallel. Autennje yellow-red; third form cordiforni. 

 pointed, sometimes blackish ; arista longer than antenna. Palpi and proboscis 

 yellowish, the latter one-half of the head height. Thoracic bristles yellow, 



TRANS. AM. ENT. SOC, XXVIII. JULY, 1902. 



