Conversely, another small group of 
species previously placed in Phytomyza , 
with the crossvein lacking, are refer- 
able to Napomyza on the basis of the 
male terminal ia, in which a narrow 
vestige of sternum 8 is present, 
partially fused to tergites 6-8 (see 
Spencer, 1976a: fig. 623, N. 
nigritula ) . Three such species are 
recorded here. 
Three general characteristics of 
Napomyza — but which are not of strict 
generic significance — are the 
projecting frons (fig. 1062), the 
short second costal section in the 
wing (fig. 1059), and the normally 
ash-gray mesonotum. The scutellum is 
generally gray but is yellow in N. 
pallens (and also in a sister species 
N. elegans in the Palaearctic Region). 
Typical Napomyza species feed and 
pupate internally in stems or flower 
heads. This explains why no species 
have been reared in the United States, 
with little or no specialized 
collecting involving the examination 
of stems having been undertaken. How- 
ever, both N. evanescens and N. margin - 
alis have been reared from Ranunculus 
stems in Canada, the former also in 
Europe . 
Less than 50 species are known 
throughout the world, mainly in the 
Nearctic and Palaearctic Regions. The 
genus is largely absent from the 
Southern Hemisphere, but four species 
have been recorded in the Afrotropical 
Region. Twelve species have now been 
identified in the United States, of 
which 2 are new. One new combination 
is established (part 2, p. 307). Six 
other species are known in Canada 
(Spencer, 1969a). 
Differences in external characters and 
in the male genitalia between species, 
which are certainly distinct and reared 
from unrelated host plants, are fre- 
quently slight. Other such probably 
undescribed species have been seen, 
but their formal description is 
undesirable until additional material, 
preferably reared, is available for 
accurate diagnosis and recognition of 
significant differentiating characters. 
Key to Napomyza 1. Outer crossvein present 2 
Species — Outer crossvein lacking 10 
2 (1). Scutellum partially or largely yellow 
N. pallens Spencer 
Synopsis. Frons broad, 3 times width of eye, 
distinctly projecting above eye in profile; gena 
broad, up to 0.5 height of eye at rear; wing 
length from 2.75 mm (Colorado) to 3.8 mm, discal 
cell minute, outer crossvein in continuation of or 
even basad of inner; frons, orbit, gena, and face 
entirely yellow; 1st antennal segment yellowish, 
2d and 3d black; mesonotum matt grayish black; 
scutellum broadly yellow centrally, with small 
black patches at sides; notopleuron, humerus, and 
upper 3d of mesopleuron yellow; legs black, all 
knees bright yellow; abdomen largely yellow, 
tergites variably grayish centrally; squama yel- 
low, fringe blackish; male genitalia with aedea- 
gus as in figures 1057, 1058; sperm pump with nar- 
row blade. 
Host/Early Stages. Unknown. 
Distribution. California; new record: Colorado, 
Clear Creek Co., Mt. Evans, 9,800 ft, Doolittle 
Ranch, 1 m. , 12. VII. 61 (C. H. Mann, CNC) ; 5 m. , 
168 
