Mesonotum. Acr irregular, in 2-3 rows. 
Wing. Length in male 2.4 mm, 2d 
costal section short, 1.67 length of 
4th. 
Color. Frons basically orange yellow, 
faintly infuscated on upper half; 
orbit and gena yellow, hindmargin of 
eye, palpus, 2d and 3d antennal 
segment black, 1st paler, slightly 
yellowish; mesonotum matt grayish 
black, side of thorax dark; legs black 
but all knees bright yellow; squama 
gray, margin and fringe black. 
Male genitalia. Aedeagus (figs. 1245, 
1246) with supporting sclerites only 
slightly diverging, distinctly dilated 
at apex but not solidly club shaped; 
ejaculatory duct strongly developed, 
with large, flaplike sclerite below 
extending symmetrically on either 
side; sperm pump minute. 
Host /early stages. Unknown. 
Holotype m. , Colorado, Boulder Co., 
Nederland, Caribou, 10,000 ft, 18. VI. 61 
(B. H. Poole), in CNC. 
Remarks. Although this species 
closely resembles Phytomyza arnicicola 
in external characters, it is distin- 
guishable by the broader gena. Its 
generic position is clearly indicated 
by the male genitalia. 
Chroma tomyia grif fithsi Spencer, new 
species 
(Figs. 1267, 1268) 
Head. Frons broad, twice width of 
eye, orbit pronounced but not pro- 
jecting above eye; 2 equal ors, 2 ori, 
lower sometimes weak or even lacking; 
gena 0.33 height of eye, parafacial 
forming broad ring below eye; 3d 
antennal segment small, round. 
Mesonotum. Acr short, irregularly in 4 
rows. 
Wing. Length from 2.5 mm in male to 3 
mm in female, 2d costal section 
slightly more than twice length of 
4th, ranging from 2.2 to 2.4 times. 
Color. Frons blackish brown on lower 
half, paler above, orbit dark brown, 
sometimes narrowly paler along inner 
margin; lunule gray; gena black to 
brownish, face, palpus, and antenna 
black; mesonotum entirely matt grayish 
black, side of thorax black; legs 
entirely black; squama gray, margin 
and fringe black. 
Male genitalia. Aedeagus (fig. 1267) 
having left basal sclerite with 
conspicuous ventral bend in rear 
third; supporting sclerites with line 
of sclerot ization at rear and broad, 
strongly pigmented sclerite in front 
in side view, in ventral (front) view 
as in figure 1268; at each side of 
curving ejaculatory duct a strongly 
pigmented sclerite below distal end of 
basal sclerites; sperm pump with 
lightly pigmented, rounded blade and 
extended base on one side. 
Host/early stages. Unknown. 
Holotype m. , Colorado, Clear Creek 
Co., Mt. Evans, Summit Lake Flats, 
12,600 ft, 24. VII. 61; paratypes 2 m. , 
2 f., 1 m. , on tundra, 2. VII. 61, other- 
wise same data; (all C. H. Mann). 
Holotype and paratypes in CNC, 2 
paratypes in KAS. 
Remarks. This species superficially 
closely resembles Phytomyza nigri- 
nervis , which occurs at the same 
locality, but the frons is paler 
behind, the third antennal segment is 
smaller, and the second costal section 
is consistently longer. There is no 
indication of the host plant. 
We take pleasure in naming this 
species after Dr. Graham C. D. 
Griffiths, whose recent work has been 
invaluable in clarifying North 
American species in this genus. 
Chroma tomyia involucratae (Spencer) 
(new to U. S. A. ) 
(Figs. 1259, 1260) 
326 
Phytomyza involucratae Spencer, 1969a: 
