TAXONOMY OF MUSCOIDEAN FLIES — TOWNSEND Jj 



and third joints equal in length; the latter has them more rufous, 

 the third joint being distinctly longer than the second as a rule. 

 L. nigricornis has the sides of abdomen somewhat reddish at base, 

 and the femora and tibiae more or less so as well. Both species 

 Tjelong in Lewcostoma. The genus Phyto has the cheeks and para- 

 facials much widened, the cheeks about one-half eye height. 



The species atra Townsend and neomexicana Townsend are like- 

 wise distinct forms, and do not belong to Phyto. It is doubtful if 

 they can be properly referred to Lcucostonia. 



Lcucostoma analis Meigen. — This species should not be recorded 

 from America, as van der Wulp was presumably in error in his 

 determination of it in Mexican material. 



Subfamily I'haxii.wt-; 

 Genus Hemyda Robineau-Desvoidy 



Hemyda an rata Robineau-Desvoidy. — The males of this species 

 have the yellow of third segment wider than the females, but only 

 slightly so, and nowhere nearly approaching in that respect the form 

 described below from New Mexico. There are eight specimens of 

 this form in the U. S. N. M., from Missouri, Kansas, Illinois, and 

 Wisconsin, one of them being labeled "attracted to light, July, 1876" 

 (Riley Coll.). 



It is interesting to note that one of the above specimens, from 

 Milwaukee, Wis., has the small cjossvein of both wings practically 

 absent; frontal bristles long, numerous, and thickly placed, and 

 vibrissa? distinct, as in several others of the specimens. 



Hemyda sp. — One male, Rio Ruidoso, White Mountains, New 

 Mexico (Townsend), about 6,500 feet, August 1, on flowers of 

 Monardq stricta. Length, 12 mm. Differs from all the above speci- 

 mens by having the yellow of third segment taking up anterior two- 

 thirds of length of segment except a median triangular prolongation 

 anteriorly of the black of hind portion, which stops well before 

 anterior edge of segment. The femora .have only a faint trace of 

 the black of aitrata in a tinge of brown before apex. The yellow of 

 second abdominal segment is more extended forward also. The 

 specimen shows only microscopic vibrissa?, invisible save with a 

 high-power lens. 



This specimen probably represents a distinct form, but it is not 

 deemed wise to name it as such without first securing a considerable 

 series of specimens to substantiate its claim to distinctness. 



