594 PROCEEDINGS OF THE NATIONAL MUSEUM VoL. 113 
This species is very similar to H. serrata (Linnaeus), except as fol- 
lows: usually a second pair of oral vibrissae; 2 or 3 irregular rows of 
buccal setae; at least 3 sternopleural bristles; male hind basitarsus 
thickened and shorter than the following segment. The structure of 
the male terminalia also distinguishes the two species from each other. 
Lenetu.—3.5-5.5 mm. 
DistripuTion.—Alaska, British Columbia, Colorado, Minnesota, 
Iowa, Wisconsin, Michigan, Indiana, Kansas, Missouri, Arkansas, 
Tennessee, Kentucky, West Virginia, Virginia, Maryland, Pennsyl- 
vania, New York; collected from March to October and from caves 
during December. 
Brotoay.—Larvae of this species from various birds’ nests have 
been reared (Blair, 1931; Collin, 1939). 
Heleomyza nebulosa (Coquillett) 
Fiaures 95, 96 
Leria nebulosa Coquillett, 1910a, p. 129.—Czerny, 1924, p. 159. 
I have examined the type (No. 13098), a female, in the U.S. National 
Museum. It resembles H. serrata (Linnaeus) very closely except as 
follows: 4 to 5 rows of buccal setae; legs reddish brown, femora grayish ; 
wings clouded with brown in region of anterior crossvein; posterior 
crossvein dark, but not conspicuously clouded; abdomen dark 
grayish brown. 
I obtained a male specimen from the Garrett collection. It was 
collected on snow, Sulfur Mountain, Banff, Alberta, 29 Mar. 1909; 
this is the type locality. No other records of the species are known to 
me. 
Heleomyza difficilis, new species 
This species is described from 2 males loaned me by the U.S. 
National Museum and a single female from the American Museum of 
Natural History. The haired pteropleuron will distinguish it from 
other species of Heleomyza. 
MaLE AND FEMALE.—Head similar to H. nebulosa (Coquillett) ; 
antennae dark brown; cheek-eye ratio about 0.5; remainder of body 
rather uniformly ash gray, except terminalia and legs are slightly 
yellowed; a faint brown median vitta lies between the dorsocentrals, 
and the brownish patches at the bases of the dorsocentrals may give 
the impression of 2 lateral vittae; anterior corner and posterior half of 
mesopleuron covered with hairs; anterior portion of pteropleuron and 
entire sternopleuron similarly covered with hairs; 1 sternopleural 
bristle; wings hyaline, anterior crossvein clouded (more so in the 
female specimen than in the 2 males). 
Lrenetu.—3.0-4.0 mm. 
