HELEOMYZID FLIES NORTH OF MEXICO—GILL 591 
dark brown to blackish; mesopleuron with several small setae in lower 
hind corner. 
DistrinuTIon.—British Columbia; June. 
Heleomyza tristissima (Garrett) 
Figure 91 
Leria tristissima Garrett, 1921, p. 122. 
Helomyza tristissima (Garrett), Czerny, 1924, p. 154. 
MALE AND FEMALE.—Entire body, except head, rather uniformly 
dark grayish brown to black; head similar to H. serrata (Linnaeus), 
sometimes 1 or 2 pairs of secondary oral vibrissae in addition to the 
stronger, primary pair; thoracic chaetotaxy similar to H. serrata 
(Linnaeus), except mesopleuron with 1-3 bristles near middle of 
posterior margin. 
Lenetu.—3.0—-5.0 mm. 
Distrisution.—Described from a male collected at St. Anthony, 
Newfoundland, May 4; all other records from Alaska (April and May). 
Brotoay.—I have collected adults in traps baited with excrement. 
Remarks.—Garrett’s unpublished notes indicate that he suspected 
that this species might be synonymous with H. modesta Meigen of 
Europe. I have examined European specimens of the latter species 
and find them indistinguishable from H. tristissima (Garrett) and H. 
czernyi Collart, except that the male terminalia are very different in 
each of the three species. 
Heleomyza czernyi Collart 
Helomyza czernyi Collart, 1933, p. 402. 
This species may be distinguished with certainty only by the male 
terminalia. Collart’s original description includes an excellent il- 
lustration of the terminalia of this species, as well as of H. modesta 
Meigen. The epiphallic processes are broad distally, as in H. modesta 
Meigen, but there are stout spines present on the medial surfaces 
of these processes in H czernyi Collart, whereas no such spines occur 
in H. modesta Meigen. 
I have examined a male and a female of this species from Greenland 
in the U.S. National Museum. They were incorrectly identified by 
Aldrich as H. modesta Meigen. The specimens agree with Collart’s 
original description, except that the legs do not seem as dark as 
described, and both specimens have a seta above the oral vibrissae. 
Collart used the absence of such setae in czernyi to separate it from 
modesta in a key to the species of Heleomyza, but I do not feel that 
this is a reliable character for use in species discrimination. 
626053—62——7 
