HELEOMYZID FLIES NORTH OF MEXICO—GILL 507 
Suillia barberi (Darlington) 
Figures 9, 10 
Helomyza barberi Darlington, in Aldrich and Darlington, 1908, p. 93. 
Suillia barberi (Darlington), Czerny, 1924, p. 15. 
This species is very similar to Sudllia nemorum (Meigen). The 
structure of the male terminalia is the most reliable character for dis- 
tinguishing S. barbert (Darlington). The hairs of the aristae are shorter 
and the forefemora usually darker in this species. 
Mae AND Frmaues.—Head similar to S. apicalis (Loew); a dark 
spot present between the eye and antenna; aristae short pubescent, the 
hairs usually less than twice the diameter of the base of the arista; 
cheek to eye ratio from 0.40 to 0.50. 
Thorax reddish yellow to dark brown; bristles and setae of mesono- 
tum usually arising from brownish spots; scutellum with setae present 
over most of dorsum; mesopleuron with setae scattered over most of 
posterior half; legs with forefemora darkened, almost black (thickened 
in male); wings strongly infuscated along crossveins and ends of longi- 
tudinal veins and along costal margin; abdomen reddish orange to 
reddish brown. 
Lrnetu.—5.5-6.0 mm. 
DistrrBuTiIoN.—Throughout western United States and Canada 
from Alberta to Texas, and from South Dakota, Nebraska, Quebec, 
and Nova Scotia; February—October. 
Suillia nemorum (Meigen) 
Ficurss 11, 12 
Helomyza nemorum Meigen, 1830, p. 52.—Zetterstedt, 1847, p. 2439.—Loew, 1859, 
p. 22._Schiner, 1864, p. 28.—Rondani, 1867, p.123.—Czerny, 1904, p. 223.— 
Aldrich and Darlington, 1908, p. 93. 
Helomyza assimilis Loew, 1862a, p. 226 (Centuria 2, 87). 
Suillia assimilis (Loew), Czerny, 1924, p. 18. 
Suillia nemorum (Meigen), Czerny, 1924, p. 20.; 1927a, p. 16. 
This species is very similar to Swillia barberi (Darlington), except as 
follows: aristae long pubescent to plumose, the hairs usually more than 
twice the diameter of the base of the arista; forefemora usually pale. 
As mentioned above, the structure of the male terminalia is the 
most reliable character for distinguishing this species from S. barbert 
(Darlington). 
Although some variation in the relative length of the hairs of 
the aristae exists in the specimens which I have assigned to this species, 
I find an intergradation which prevents me from dividing the speci- 
mens into two groups on the basis of this character. Furthermore, 
I find them all alike so far as male terminalia and other basic char- 
