narrow, 0.20 height of eye; ocellar triangle and 
orbit distinctly but moderately shining; male 
genitalia with aedeagus as in figures 56, 57. 
Host /Early Stages. Unknown. 
Distribution. Long Island, N.Y. 
Reference. Part 2, p. 245. 
— 2 ori; frons little wider than eye; arista distinct- 
ly pubescent M. virginiensis Spencer, n. sp. 
Synopsis. Large species, wing length 2.75 nyri in 
male; orbital setulae in 2 rows, inner row largely 
proclinate, outer more reclinate; gena about 0.20 
height of eye; male genitalia with aedeagus as in 
figures 58, 59. 
Host/Early Stages. Unknown. 
Distribution. Virginia. 
Reference. Part 2, p. 248. 
29 (18). Gena deepest in front (fig. 60) M. buccalis Spencer 
Synopsis. Small to medium-sized species, wing 
length from 2 to 2.3 mm in male to 2.8 mm in fe- 
male; frons not projecting above eye; 2 ors, 
either 2 or 3 ori; eye in male distinctly pilose; 
mesonotum appearing matt, blackish from front, more 
greenish from rear; abdomen greenish or coppery; 
male genitalia with aedeagus as in figures 61, 62. 
Host/Early Stages. Unknown (possibly Arnica and 
other Asteraceae, see Spencer, 1981). 
Distribution. California; new records: Colorado, 
Maryland, New York, Virginia; Canada. 
References. Spencer, 1969a: 67; 1981: 38; part 2, 
p. 243. 
Gena deepest in center or rear 30 
30 (29). Orbits conspicuously widening at midpoint 31 
— Orbits not so widening 32 
31 (30). Each orbit over 0.33 width of frons; orbital 
setulae numerous, conspicuously proclinate 
above M. virens (Loew) 
Synopsis. Medium-sized species, wing length 2.2-3 
mm; 2 ors, 2 ori; gena narrow, eye pilose in male; 
mesonotum and abdomen greenish; male genitalia 
with aedeagus as in figures 63, 64; surstylus 
projecting inward, with 3 or 4 strong, spinelike 
projections at end (fig. 65). 
Host/Early Stages. Eupatorium capillifolium . 
Heterotheca subaxillaris . Puparium straw 
colored, posterior spiracles widely separated, 
each with about 8 well-defined bulbs around strong 
central horn (fig. 66). 
Distribution. Florida, Pennsylvania, South 
Carolina (confirmed), certainly more widespread; 
widespread in Canada. 
Reference. Spencer and Stegmaier, 1973: 51. 
— Orbit broad but less than 0.33 width of frons; 
orbital setulae less numerous, less proclinate 
above M. splendida Frick 
Synopsis. Medium-sized species, wing length 
2. 2-2.7 mm; frons not projecting; 2 ors, 2 ori; 
25 
