Key to Hexomyza 1. Costa ending shortly after termination of vein 
Species R 4+5, possibly attenuated toward M 1+2 2 
Costa extending strongly to vein M 1+2 5 
2 (1). Wing conspicuously white, veins pale or colorless 
H . winnemanae (Mai loch ) 
Synopsis. Frons broad, twice width of eye, pro- 
jecting above eye in profile; 2 equal ors, 2 slender 
ori, orbital setulae reclinate above, more upright 
below; gena deepest in center, almost 0.33 height of 
eye; 3d antennal segment small, round, arista short, 
appearing almost bare; mesonotum with 2 dc, black; 
abdomen more shining; wing length 2-3 mm; male 
genitalia with aedeagus as in figures 143, 144. 
Host/Early Stages. Salix spp. Larva forming twig 
gall; puparium gray, posterior spiracles in form of 
2 short, stout projections (fig. 145), which are 
adjoining and largely fused, probably each with 3 
minute bulbs (although not detectable in only 
available specimen). 
Distribution. Maryland; Canada. 
References. Malloch, 1913a: 314; Spencer, 1969a: 79 
(as H. albicula ) ; part 2, p. 250. 
Wing hyaline, normal, veins pale or darker brown 3 
3 (2). Small species, wing length in male 1.9-2. 3 mm 4 
Larger species, wing length 2. 5-3. 8 mm 
H. simplicoides (Hendel) 
Synopsis. Frons matt black, broad, twice width of 
eye, strongly projecting above eye in profile; nor- 
mally 2 ors and 2 or 3 ori, orbital setulae con- 
spicuously long, reclinate or frequently distinctly 
incurved; gena broad, up to 0.33 height of eye; 
mesonotum shining black, normally with 2 dc, 
2d close to 1st and well behind level of supra-alar, 
frequently a 3d also present; costa normally ending 
just beyond vein R 4+5, sometimes continuing weakly 
toward M 1+2; outer crossvein often lacking; male 
genitalia with aedeagus as in figures 146, 147. 
Host/Early Stages. Salix spp. Larva forming oval 
twig gall (see fig. 157), each posterior spiracu- 
lar process having 3 minute bulbs on short, broad 
stalk, front segments conspicuously cut away and 
in puparium bright reddish brown (fig. 148). 
Distribution. California, New York, Ohio. 
Reference. Spencer, 1981: 31. 
4 (3). 2 ors, 3 ori; 2 dc H. toschiae Spencer 
Synopsis. Frons unusually broad, 2.5 times width 
of eye, conspicuously projecting above eye; orbit- 
al setulae sparse, upright or reclinate; ocellar 
triangle large, apex extending to middle ori; gena 
angular, 0.20 height of eye; mesonotum matt viewed 
from front, weakly shining from rear, abdomen more 
shining black; squama gray, margin and fringe 
black; wing length in male 1.9 mm; male genitalia 
with aedeagus as in figures 149, 150. 
Host/Early Stages. Unknown. 
Distribution. California. 
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