forward; vibrissal angle approx. 45°; fasciculus 
in male short but broad (fig. 224); facial keel 
broad, low; wing length in male 1.9 mm, last 
section of M 3+4 little shorter than penultimate; 
male genitalia with aedegus as in figures 225, 226. 
Host/Early Stages. Unknown. 
Distribution. Northern California. 
Reference. Spencer, 1981: 72. 
Facial keel narrow 0. chondrillae Spencer, n. sp. 
Synopsis. Frons narrow, equal to width of eye; 
gena broad, projecting forward, with unfused vi- 
brissal fasciculus (fig. 227); wing length in male 
2 mm, last and penultimate sections of vein M 3+4 
equal; male genitalia with aedeagus as in figures 
228, 229. 
Host/Early Stages. Chondrilla j uncea « Larva form- 
ing external stem mine. 
Distribution. Washington. 
Reference. Part 2, p. 253. 
29 (27). Frons broad, twice width of eye 30 
Frons narrower, at most 1.5 times width of eye 31 
30 (29). Gena broad, 0.33 height of eye 
0. subpraecisa Spencer, n. sp. 
Synopsis. Frons not projecting above eye; fasci- 
culus in male short; facial keel broad, conspicu- 
ously raised, with low furrow on upper half; 
wing length 2. 1-2.3 mm; ocellar triangle weakly 
shining; mesonotum and abdomen more distinctly 
shining black; male genitalia with aedeagus as in 
figures 230, 231. 
Host/Early Stages. Unknown. 
Distribution. Colorado. 
Reference. Part 2, p. 258. 
Gena narrow, 0.20 height of eye 0. ambrosia Spencer 
Synopsis. Wing length in male 2.1 mm; 2 ori; 
fasciculus in male broad at base, with conspicuous 
bend beyond midpoint (fig. 232); facial keel nar- 
row, raised below base of antennae, without fur- 
row; mesonotum and abdomen moderately shining 
black, latter with faint coppery reflections; male 
genitalia with aedeagus as in figures 233, 234. 
Host/Early Stages. Unknown. 
Distribution. California. 
Reference. Spencer, 1981: 71. 
31 (29). Facial keel high, rounded 32 
— Facial keel only slightly raised 33 
32 (31). Vibrissal fasciculus in male long, slender (fig. 235) 
0 . quinta Spencer 
Synopsis. Wing length 2 mm; vibrissal angle acute, 
approx. 45°, fasciculus regularly curving (fig. 
235); facial keel high, without central furrow; 
mesonotum and abdomen shining black; male geni- 
talia with aedeagus as in figures 236, 237. 
Host /Early Stages. Aster , Solidago . Larva forming 
long, narrow, upper surface leaf mine, with frass 
in conspicuous, widely spaced black pellets (fig. 
45 
