THE CANADIAN ENTOMOLOGIST. 249 



the second antennal segment and equal to about two-fifths the distance between 

 the vibrissae. Facial ridges bristly on lowest fourth. Facial depression silvery 

 pollinose, without any carina. Antennae in male reaching the lowest fourth of 

 the face, all three segments black ; third segment in male about one and one- 

 half times as long as the second. Arista thickened on basal two-fifths to one- 

 half, the penultimate segment scarcely longer than broad. Width of front in 

 male at narrowest point measuring slightly less than the length of the second 

 antennal segment ; the front silvery pollinose ; frontal vitta dull, dark brown, at 

 narrowest pomt — in male — slightly wider than either side of front just cephalad 

 of the ocellar triangle. No orbital bristles in male, the proclinate ocellars 

 somew^hat weak and reduced in cases to mere hairs ; the single row ot frontal 

 bristles decending nearly to the base of the third antennal segment. 



Thorax subshining, black, covered w4th gray pollen ; scutellum gray 

 pollinose on a black ground in most specimens tinged reddish, especially at the 

 apex. Typically three sternopleural bristles but considerable variation notice- 

 able in the type material ; typically four dorsocentral bristles, but these like- 

 wise vary considerably in the type material ; scutellum with three marginal 

 pairs of machrochaetae and an apical cruciate pair. Legs black, the middle 

 tibiae with two or more bristles on the front side near the middle, the hind 

 tibiae without a comb-like row of bristles on the outer side. Wings hyaline ; 

 R4+5 (third vein) with a group of two to five hairs both above and below at 

 the junction with R2+3. Tegulae white. 



Abdomen subshining ; silvery pollinose on a black ground that occasion- 

 ally becomes reddish, particularly on the lateral parts of the first three segments. 

 Discal machrochaetae present on the second, third and fourth abdominal seg- 

 ments ; median marginals present on the same segments. The hind mar- 

 gin of the third tergum strongly arcuate. The fifth tergum distinctly 

 marked ofT by a suture from the sixth or first genital segment and 

 laterally being a third as long as the lateral part of the fourth abdominal 

 segment. The sixth and seventh abdominal segments forming somewhat dis- 

 tended genital segments. 



Male genitalia black. The basal part of the outer forceps is expanded 

 into a broad, leaf-like portion. The basal part of the inner forceps is equipped 

 with a short median, keel-like projection, the basal edge of which is concave in 

 profile. 



The horseshoe-like indenture extends rather more than half way to the 

 base of the fifth sternite. 



Described from ten males taken at Great Falls. Va., (type locality), 

 Mount Vernon, Va.. Cabin John Bridge, Maryland. Bladensburg, Md., Plum- 

 mers Island, Md., Hartford, Conn., Maiden, Mass.. and North Saugus, Mass. 

 Material collected in April and May. 



Type No. 24355 in the U. S. N. M., Washington, D.C. A paratype 

 in the National Collection at Ottawa. 



Ernestia incisa sp. n. 



Description of male. Head at vibrissae nearly as thick as at base of 

 antennae, vibrissae far above the oral margin. Palpi in the single type speci- 



