96 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



composed of several species of attenuated or possibly discontinuous 

 distribution. Not one of the species is definitely known to have a 

 transcontinental range, and specimens from west of the Mississippi 

 River are not frequently seen in collections. Possibly polita has the 

 widest range, being recorded from Ithaca, New York, to the Animas 

 Mountains, New Mexico, and Florida. Very little is known of the 

 ecology of any of the species of this genus. Scattered information 

 indicates that they frequent low foliage and may be attracted to 

 flowers. Nathan Banks writes that the adults of some species are 

 found feeding frequently on honeydew falling from the tulip tree, 

 Liriodendron tulipifera, in Virginia, and W. L. McAtee has collected 

 another species on the flowers of Ceanothus americanus. Nothing is 

 known of the host relationships in this group. 



KEY TO NORTH AMERICAN SPECIES OF QYMN0PR030PA 



1. Parafacials with black bristly hairs 4. 



Parafacials bare, or at most with minute, scarcely visible hairs 2. 



2. Last three segments of abdomen poUinose on basal half, the pollinose bands 



thickly beset with black bristly hairs; extreme lateral pair of scutellar 



bristles as strong as the apicals; preapicals present ,_3. 



Last three segments of abdomen pollinose on basal third of segment; pollinose 

 bands almost free of bristly hairs; bristles of third abdominal segment as 

 strong as those of fourth; extreme lateral pair of scutellar bristles weaker 

 than apical pair; preapicals lacking; front pulvilli of male less than half as 

 long as last tarsal joint polita Townsend. 



3. Frontal vitta pale yellow; third v'ein with one small bristle near its base; 



hind cross vein nearly parallel to section of fourth vein beyond the bend; 

 front pulivilli of male one-fourth as long as last tarsal joint; first and second 



abdominal segments with red on sides pallida, new species. 



Frontal vitta dark yellow to red; third vein with two or three bristles at its 

 base; hind cross vein not parallel to section of fourth vein bej'ond the bend 

 but perpendicular to preceding section; front pulvilli of male as long as 

 last tarsal joint; first and second abdominal segments witliout red on the sides 



argentifrons Townsend. 



4. With three or four proclinate orbital bristles; palpi clavate; third antennal joint 



conspicuously inflated; second and third abdominal segments pollinose on 



basal half inflaticornis, new species. 



With only two proclinate orbital bristles; palpi filiform; third antennal joint 

 not inflated; second and third alxlominal segments i)o]linose on basal third. 



fllipalpus, new species. 



GYMNOPKOSOPA POLITA Townsend 



Gymnoprosopa polita Townsk.vd, Trans. Amer. Ent. Soc, vol. 19, p. 109, 



1892. 

 Gymnoprosopa clarifrons Townsexd, Trans. Amer. Ent. Soc, vol. 19, p. 109, 



1892. 

 Hilarella polila Coquillett, U. S. Bur. Ent., Tech. Ser., No. 7, p. 128, 1897. — 



Aldrich, Cat. of N. A. Diptera, p. 447, 1905. — Smith, Ins. of New Jersey, 



p. 782, 1909.— Johnson, Bull. Amer. Mus. Nat. Hist., vol. 32, p. 73, 1913. 



After reexamining types of polita, argentifrons, and clarifrons 

 together witli a fairly long series of specimens not i>reviously available 



