Key to Cerodontha , 
Subgenus Dizygomyza 
Species 
1 . 
2 ( 1 ). 
3 ( 2 ). 
4 (1). 
5 (4). 
Notopleuron yellow 
Notopleuron dark 
All tergites broadly yellow laterally 
“ C. (D. ) pecki Spencer 
Synopsis. Frons broad, twice width of eye, 2 ors, 
2 ori; lunule semicircular; gena narrow, 0.17 
height of eye; 3d antennal segment (fig. 593) 
enlarged in both sexes, conspicuously pubescent; 
mesonotum ash gray, humerus and notopleuron 
bright yellow; legs black but foreknee bright 
yellow; abdomen with all tergites broadly yellow 
laterally and narrowly so on hindmargin; squama 
and fringe yellow; wing length 1 . 8 - 1. 9 mm, last 
and penultimate sections of M 3+4 approx, equal; 
male genitalia with aedeagus having distal 
tubules diverging and enlarged at end (fig. 594 ). 
Host/Early Stages. Unknown. 
Distribution. Florida. 
Reference. Spencer and Stegmaier, 1973: 161. 
Tergites largely black 3 
Large species, wing length 3. 2-3.4 mm 
C. (D. ) thompsoni (Frick) 
(Notopleuron normally darker, couplet 8 ) 
Smaller species, wing length less than 2.5 mm 
C. (D. ) magnicornis (Loew) 
Synopsis. Frons broad, twice width of eye, 2 ors, 
2 ori; lunule semicircular, gena narrow, about 
0.125 height of eye; mesonotum grayish black; 
rear of humerus and notopleuron yellow; abdomen 
largely black, hindmargin of tergites only narrow- 
ly yellow; legs black but all knees yellow; squama 
and fringe yellow; wing length 2 . 2 - 2.4 mm, last 
section of M 3+4 distinctly longer than penulti- 
mate; male genitalia with aedeagus (fig. 595 ) 
having paired tubules of distiphallus only slight- 
ly curving at base and apex. 
Host/Early Stages. Unknown. 
Distribution. Illinois, Indiana, Michigan, New 
Hampshire, Pennsylvania; new records: Colorado, 
Boulder Co., Vrain Creek, 3 miles S.W. of Raymond, 
8,200 ft, 1 f., 11. VIII. 61 (J. G. Chillcott , CNC) ; 
Tennessee, Knox Co., Knoxville, University Farm, 
1 m., 20.V.57 (J. R. Vockeroth, CNC). 
References. Frick, 1959: 384; Spencer, 1969a: 121 
(as C. morosa ) ; Nowakowski, 1973: 222; part 2, 
p. 283. 
All knees conspicuously yellow 5 
Only foreknee conspicuously yellow 9 
Frons broad, 3 times width of eye 
C. (D. ) latifrons Spencer, n. sp. 
Synopsis. Frons distinctly projecting above eye; 
orbit yellow, strongly differentiated from dark 
brown frons; 2 ors, 3 ori; gena 0.20 height of 
eye; 3d antennal segment enlarged in male, thickly 
pubescent; mesonotum matt gray, abdomen slightly 
yellow laterally and tergites narrowly yellow 
101 
CM <t 
