1921] Van Duzee — A Few North American DoIicJwpodidce 123 



Proarchus (Phylarchus) Aldrich. 



Dr. Aldrich described this genus from two females taken in 

 Mexico, and has placed the genus in the Thinophilinse. I have a 

 species found in New York and Virgina which I am placing in 

 that genus. It has the antenna3 and plumose arista as in his spe- 

 cies, the face of the female is as he described it (about as in Pelas- 

 tonerus). My specimens have distinct acrostichal bristles, while 

 his species was destitute of these bristles. The hypypygium of 

 this new species is large, extending forward under the venter, as 

 in Dolichopus and its lamella are as in that genus (fig. 3). If 

 the male of his species proves to have the hypopygium as in my 

 species, it would place the genus in Dolichopodinse, I should say 

 after Polymedon, or perhaps after Sarcionus and next to Pelas- 

 toneurus, from which it is separated by its nearly parallel third 

 and fourth veins. 



This would place the genus near the European genus Poecilob- 

 thrus Mik. The female of the only species of that genus that I 

 have seen, P. nobilitans, has the face formed very much as in 

 Pelastoneurus and has a plumose arista. I should place our species 

 in that genus, only the second and third veins are not approxi- 

 mated nor the wing of the male ornamented with black as in all 

 species of Poecilol^othrus known to me. 



Proarchus violaceus sp. nov. 



Male: Length 4—4.5 mm.; of wing 4 mm. Face wide, covered 

 with gi-ayish-white pollen, sometimes almost silvery, upper portion 

 a little concave and with a slightly depressed median line, the 

 lower part rather short and slightly convex. Front dark violet, 

 sometimes almost black, a little dulled with brown pollen. Palpi 

 yellow with black hairs and a little white pollen. Antennse (fig. 2) 

 yellow; third joint sometimes mostly Ijrown, short, somewhat oval 

 in outline; arista dorsal, distinctly plumose, although the hairs 

 are not long. Orl)ital cilia wholly black. 



Dorsum of the thorax violet with the lateral and anterior mar- 

 gins quite broadly greenish; acrostichal bristles rather large, in 

 two rows; scutellum violet with two large and two very small 

 bristles on its margin; pleurae more black with gray pollen. Abdo- 

 men green with white pollen; incisures black; hind margins of 

 segments with stiff black bristles. Hypopygium (fig. 3) formed 



