HELEOMYZID FLIES NORTH OF MEXICO—GILL 499 
evidence of such a bristle on the opposite side); anterior crossvein of 
wing darkened; posterior crossvein very slightly, if at all, darkened. 
DistRiBnuTION.—Boston, Mass.; 19 October. 
Genus Suillia Robineau-Desvoidy 
Helomyza Fallén, 1820, p. 3 (part).—Meigen, 1830, p. 47 (part).—Macquart, 
1835, p. 410 (part).—Zetterstedt, 1838, p. 764 (part); 1847, p. 2430 (part).— 
Loew, 1859, p. 17.—Schiner, 1864, p. 23.—Rondani, 1867, p. 116.—Pandellé, 
1901, p. 335 (part).—Czerny, 1904, p. 212.—Aldrich and Darlington, 1908, 
p. 89.—Collin, 1943, p. 237. 
Suillia Robineau-Desvoidy, 1830, p. 642.—Czerny, 1924, p. 8; 1927a, p. 6.— 
Steyskal, 1944, p. 173. 
Herbina Robineau-Desvoidy, 1830, p. 698. 
Heteromyza Fallén, Zetterstedt, 1838, p. 763 (part). 
The preceding key to the subfamilies and the key to the genera of 
the Suillinae include the important generic characters of Suwillia. 
The general body coloration ranges from pale yellow to reddish 
brown. Whereas in the Heleomyzinae the aristais bare to pubescent, 
the arista in the Suilliinae is pubescent to plumose, depending upon 
the species. The thoracic chaetotaxy is as follows: dorsocentrals 
1-++4, prescutellar bristles absent, humeral bristle absent, 1 presutural 
bristle, 2 notopleural bristles, 3 supra-alar bristles, 2 pairs of lateral 
scutellar bristles; propleural bristle absent, mesopleuron variable, 
1 sternopleural bristle, remainder of pleura bare. 
Male Suillia may be separated on the basis of characters other than 
the terminalia; however, the shape of the surstylus is generally 
distinctive. 
Key to the Species of Suillia 
1. Mesopleuron with setae or hairs (may be confined to posterior edge). . . . 2 
Mesopleuron bare .. . Alar ea at 
2. Secutellum with hairs of domuns peace: a the ineeral ieee mostly bare. 
apicalis (Loew) 
Scutellum with hairs widely distributed on dorsum... . a oon ae? te) 
3. Ends of longitudinal veins without distinct infuscations; erbitooansennall spot 
absent; male with long hairs on ventral side of tibiae and posterior side of 
Mebatarsi of fore and middle legs (cf. 9 below) . . . . longipennis (Loew) 
Ends of longitudinal veins with distinct infuscations; orbito-antennal spot 
IESeNbies cates cae he toe Chote) 
4. Arista pubescent, the ne eee en pan imice the diemcret of the base of 
the arista; forefemora dark, may be almost black . . barberi (Darlington) 
Arista long nmeercon to plumose, the hairs usually more than twice the diam- 
eter of the base of the arista; forefemora usually pale . nemorum (Meigen) 
5. Scutellum bare; wings without infuscations. . ... . . .loewi (Garrett) 
Scutellum with hairs, at least between the marginal bristles; wings with at 
Leastifaimtyinnhuscationsts,.\..Ws2s: ee atis lod kd ay cu ceala) et MAllaacunes vette 6 
GriCheel-eyevratio 0:25) ortless (i sah oeelox dhe LL ATS Has etonwenstu ll 7 
Cheek-eye ratio 0.3 or greater... ... sate SO) Sh Visa essa 18 
