HELEOMYZID FLIES NORTH OF MEXICO—GILL 513 
All known North American species of this genus are characterized 
by having 8 pairs of lateral scutellar bristles instead of the usual 2 
pairs. Johannsen (1941) points out the error of Aldrich (1926) and 
Curran (1934) in including this genus with those lacking a humeral 
bristle. The humeral bristle is present in all known North American 
species. ‘The dorsocentral bristles are difficult to interpret, because they 
become weaker anteriorly. There are at least 4 or 5 pairs; Czerny 
(1924) described them as 2(3)+3(4). 
Key to the Species of Orbellia 
1. Legs (except tarsi) and palpi wholly yellow; male with long yellow hairs ex- 
tending downward from post-oral region of head . . . . berbata (Garrett) 
Legs and palpi not wholly yellow; male without conspicuous long yellow hairs 
extending downward from post-oralregionofhead. . .. . Peto &. 
2. Fore basitarsus of male shorter than second tarsal segment; malpi at least par- 
tially yellow... . . . . petersoni (Malloch) 
Fore basitarsus of aes foneee han econ farrell segment; palpi wholly 
DIA Ckaeeen emi ag honk Weontt eer ae se Mice Wns) ase acy Leal enh Mhienvalia (Loci). 
Orbellia petersoni (Malloch) 
FIGuRE 16 
Anarostomotdes petersont Malloch, 1916, p. 16. 
Orbellia petersoni (Malloch), Czerny, 1924, p. 71. 
Malloch’s original description is adequate for this species, although 
it appears that the color of the palpi is quite variable and may some- 
times approach the wholly black condition found in Orbellia hiemalis 
(Loew). 
DistrinuTIon.—Washington, Idaho, Minnesota, Iowa, Illinois, 
Michigan, Ohio, Pennsylvania, New Jersey, Maine; October—December. 
Orbellia hiemalis (Loew) 
FIGURE 17 
Crymobia hiemalis Loew, 1859, p. 46; 1862b, p. 127. 
Leria longipennis Schiner, 1864, p. 30. 
Orbellia hiemalis (Loew), Czerny, 1924, p. 72; 1927a, p. 23.—Johannsen, 1941, 
p. 202. 
Czerny (1924) described Orbellia hiemalis (Loew) as having the 
proboscis and palpi all black and the fore basitarsus of the male longer 
than the second tarsal segment. Otherwise the species is similar to O. 
petersoni (Malloch). I have not yet seen a specimen from North Amer- 
ica which I could assign with certainty to this species, although there 
are published records of the species from this area. J have examined 
European material sent to me by Linder and Hennig and find that the 
specimens conform with Czerny’s description. The general color- 
