synonym has been discovered in 
Xenophytomyza (part 2, p. 276), and 2 
species are recorded as new to the 
United States, C. (P. ) pygmaea and CL 
(D. ) fasciata. Two species must be 
deleted from the United States list: 
C. ( Dizygomyza ) iraeos (R. -D . ) and C . 
(D. ) iridis (Hendel). 
A number of random caught males have 
been examined that probably represent 
other undescribed species, but 
differences in the genitalia and 
external characters are slight and not 
distinctive and it seems preferable 
not to describe them formally without 
confirmatory biological evidence. 
The seven subgenera are keyed and 
briefly discussed here. 
Key to Cerodontha 
Subgenera 
1 . 
2 ( 1 ). 
3 (1). 
4 (3). 
5 (4). 
6 (5). 
Scutellum with 1 pair of scutellar bristles; 3d an- 
tennal segment with spine or at least angulate 2 
Scutellum with 2 pairs of scutellar bristles 3 
3d antennal segment with spine (fig. 549); partial- 
ly yellow species Cerodontha Rondani 
3d antennal segment angulate; black species 
Xenophytomyza Frey 
Costa ending at vein R 4+5; lunule distinctly 
higher than semicircle Phytagromyza Hendel 
Costa extending strongly to vein M 1+2 4 
Lunule broad, in form of semicircle (fig. 540, _C) 
or slightly higher but still broad (fig. 540, 15) — 5 
Lunule high and narrow (fig. 540, A); if lower 
(fig. 540, JB ) , 3d antennal segment angulate (fig. 
555) and notopleuron yellow (£. (P.) chill- 
cottiella ) Poemyza Hendel 
Lunule higher than semicircle (fig. 540, B ) ; 3d 
antenal segment never enlarged in male 
Butomomyza Nowak owski 
Lunule nearly semicircular (fig. 540, C) 6 
Frons dark, black or brown, lunule gray; ocellar 
triangle not extended; 3d antennal segment in male 
enlarged in United States species (except CL (D. ) 
bicolorata ) Dizygomyza Hendel 
Frons normally yellow (black only in C. [_I. ] monta- 
noides ) , lunule always yellow; ocellar triangle ex- 
tended, with apex near margin of lunule; 3d anten- 
nal segment not enlarged in male Icteromyza Hendel 
Cerodontha , Subgenus Icteromyza Hendel 
Dizygomyza ( Icteromyza ) Hendel, 1931: 
51. Type of subgenus: Agromyza 
geniculata Fallen, 1823a (Europe). 
Distinguishing characters of this sub- 
genus are the widely separated 
antennae, large semicircular lunule, 
generally yellowish frons, extended 
ocellar triangle that normally reaches 
the margin of the lunule, and large 
discal cell. Although lacking the two 
important characters of Cerodontha 
s.s., the spine on the third antennal 
segment and only a single pair of 
scutellar bristles, the male genitalia 
confirm the close relationship between 
Icteromyza and Cerodontha . 
88 
