7m., 6 f. (C. H. Mann, CNC) ; Loveland Pass, 
12,000 ft, summit, 1 m. , 7. VIII. 61 (B. H. 
Poole); Lake Co., Independence Pass, 12,100 ft, 
tundra, 1 m. , 31. VII. 671 (J. G. Chillcott). 
References. Frost, 1924: 87; Frick, 1959: 432. 
100 (98). 3d antennal segment enlarged, somewhat angular 
at upper corner (fig. 1271) 
Chromatomyia erigerontophaga (Spencer) 
Synopsis. Frons twice width of eye, blackish 
below, more brownish or even ochreous above; 2 
equal ors, generally only 1 ori but sometimes 
smaller one below; gena slightly more than 0.33 
height of eye, brownish; face, palpus, antenna 
black; mesonotum matt gray, acr variable, in 
2-4 rows; legs black but all knees conspicuous- 
ly yellow; squama pale gray, margin and fringe 
black; wing length 2. 1-2.4 mm, 2d costal sec- 
tion short, little longer than 4th; male geni- 
talia with aedeagus (figs. 1272, 1273) having 
long basal sclerites, supporting (dorsal) scle- 
rites weakly pigmented except at base, long 
straight sclerites lying ventrally and extend- 
ing forward from end of basal sclerites, left 
longer than right; distiphallus with paired 
convergent sclerites and short semicircular 
sclerotized area near end of ejaculatory duct; 
sperm pump as in figure 1274. 
Host/Early Stages. Erigeron (high elevation 
species). Larva feeding mainly in petiole or 
base of leaf, moving from one leaf to another 
via short stem; puparium yellowish white, at 
base of leaf, with anterior spiracles project- 
ing ventrally through epidermis. 
Distribution. Colorado (new record); Alaska, 
Canada, northern Greenland (Peary Land). 
References. Spencer, 1969a: 239; Griffiths, 
1976b: 261; part 2, p. 325. 
3d antennal segment small, round 101 
101 (100). Mesonotum distinctly black 
Chromatomyia nigrella Spencer, n. sp. 
Synopsis. Small species, wing length in male 2 
mm, 2d costal section 2. 5-2. 9 times length of 
4th; frons black or slightly brownish above; 2 
equal ors (normally), 1 strong ori, sometimes 
weak additional one below; acr variable, in 2 
rows in 1 specimen, 4 rows in other; legs 
black, knees distinctly yellowish; male geni- 
talia with aedeagus having slender supporting 
sclerites (figs. 1275, 1276); sperm pump minute 
(fig. 1277). 
Host/Early Stages. Unknown. 
Distribution. North Carolina. 
; Reference. Part 2, p. 328. 
Mesonotum at most blackish gray 102 
102 (101). Acr in 2 rows 103 
Acr in 4 rows 104 
209 
