HELEOMYZID FLIES NORTH OF MEXICO—GILL 589 
Key to the Species of Heleomyza 
1. Pteropleuron bare (rarely 1 or 2 hairs present). .......2.2.2... 2 
Pteropleuron haired in anterior half... .. . . . . difficilis, new species 
2. Three or more sternopleural bristles; hind basitarsus of male shorter than 
following segment... ... . . . . . brachypterna (Loew) 
One or two sternopleural aE: hina! aaa of male not shorter than 
following segment. ..... aes Comte 20 
3. Mesopleuron bare except cameunnee short Bais, or aeetaes near ironies (very 
rarely a single seta along middle of posterior margin). ........ 4 
Mesopleuron with bristles, hairs, or setae in areas other than near propleuron . 5 
4. Wings clouded with brown along anterior crossvein; abdomen grayish brown. 
nebulosa (Coquillett) 
Wings not clouded along crossveins; abdomen usually yellowish orange to 
reddish brown. . . . . . serrata (Linnaeus) 
5. Mesopleuron with panies fae or pete Perieied to middle of posterior 
margin; 1 or 2 sternopleural bristles... . . a0 
Mesopleuron with hairs or setae in areas other ean near riddle of POStetiOr 
margin; 1 sternopleural bristle. . . .. SOG asia 
6. One sternopleural bristle; mesopleuron with 1 6 3 rinee or hae near middle 
Of posterior margin... . 9.0.0. . ehae deal eiect ech Ga ti krean shitter cee a eee 
Two sternopleural bristles; daeepulsdren with several setae near middle of 
posterior margin. . . . . .. . . bisetata (Garrett) 
7. Setae of mesopleuron restricted te lower hind! corner. . genalis (Coquillett) 
Mesopleuron extensively covered with short hairs or setae. pleuralis (Becker) 
8. Distal portion of epiphallic process of male at least twice as broad as the base. 
ezernyi Collart 
Distal portion of epiphallic process of male less than twice as broad as the 
IDASEYU Liss yaa hls iihisi wv elias « Luliedtel ails te cies ts tristissima (Garrett) 
Heleomyza serrata (Linnaeus) 
Figure 89 
Musca serrata Linnaeus, 1761, p. 455. 
Heleomyza serrata (Linnaeus) Fallén, 1810, p. 19. 
Helomyza serrata (Linnaeus), Fallén, 1820, p. 4 (part).—Zetterstedt, 1838, p. 
766; 1847, p. 2450.—Czerny, 1924, p. 147; 1927a, p. 44. 
Helomyza fuscana Meigen, 1838, p. 369. 
Helomyza geniculata Zetterstedt, 1847, p. 2451 (part). 
Leria serrata (Linnaeus), Schiner, 1864, p. 29.—Rondani, 1867, p. 125.—Pandellé, 
1901, p. 346.—Collin, 1943, p. 249. 
Leria serrata var. nigricana Garrett, 1922, p. 176. 
Leris serrata var. vinus Garrett, 1922, p. 177. 
Helomyza americana Garrett, 1925a, p. 3. 
This species is very common in collections. The bare mesopleuron, 
the absence of clouding along the anterior crossvein of the wing, and 
the presence of less than three pairs of sternopleural bristles will 
distinguish this species from others in the genus. 
MALE AND FEMALE.—Front yellowish orange, darker above; upper 
half of fronto-orbital plates, ocellar triangle, vertex, and upper back 
of head ash gray; face, cheeks, and lower back of head yellow to 
