Key to Pseudonapo - 
myza Species 
1 . 
Tarsi dark brown or black; mesonotum black 
j?. atra (Meigen) 
Synopsis. Small black species; frons little wider 
than eye, conspicuously projecting above eye, 
increasingly so toward antennae; up to 5 orbital 
bristles, orbital setulae reclinate; 3d antennal 
segment angulate (fig. 1051); mesonotum deep black, 
largely matt but more shining from rear, with 3 
strong postsutural dc ; wing length 1.3-1. 7 mm, 2d 
costal section short (fig. 1052), generally about 
1.5 times length of 4th; legs entirely black; 
squama, fringe, and halter white; male genitalia 
with aedeagus as in figures 1053, 1054. 
Host/Early Stages. Poaceae; larva feeding on many 
genera, recorded in America on cultivated cereals 
Avena sativa , Hordeum vulgare , Secale cereale , and 
Trit icum aes tivum , also on Agropyron repens; in 
Europe also known on Apera , Lolium , and Poa . Larva 
forms narrow linear mine, pupating externally; both 
it and brownish puparium have rows of distinctive 
papilli around segmental boundaries (fig. 1055), 
posterior spiracles each with 7 bulbs (fig. 1056). 
Distribution. California, New Mexico, North Dakota, 
Washington; doubtless more widespread. 
References. Frick, 1959: 418; Spencer, 1969a: 209; 
1981: 348. 
Tarsi conspicuously yellowish; mesonotum gray 
P. lacteipennis (Mai loch) 
Synopsis. Generally resembling P. atra, apart from 
paler tarsi and grayish mesonotum; wing shining 
white; male genitalia unknown. 
Host/Early Stages. Unknown, presumably Poaceae. 
Distribution. Kansas, Michigan, New Mexico, North 
Dakota, Washington (Frick, 1959); widespread in 
Canada; England. 
References. Malloch, 1913b: 152; Frick, 1959: 419; 
Spencer, 1969a: 210. 
Genus Napomyza Westwood 
Napomyza Westwood (Haliday ms.), 1840: 
192. Type of genus: Phytomyza 
elegans Meigen, 1830 (as ]?. fest iva 
Meigen, 1830). 
This genus was actually proposed 
earlier by Curtis with a different 
species as type, but this has been 
universally overlooked or disregarded 
and application has therefore been 
made to the International Commission 
on Zoological Nomenclature for sus- 
pension of the rules to maintain 
stability . 
In the widely accepted concept of this 
genus, the essential characters — orbital 
setulae proclinate and costa extending 
only to vein R 4+5 — are as in Phyto - 
myza , and Napomyza was differentiated 
by the presence of the outer crossvein, 
with the discal cell small (fig. 1059). 
Examination of male genitalia in recent 
years has shown that a few leaf-mining 
species with the crossvein present cor- 
rectly belong in Chromatomyia or Phyto - 
myza , and two such species in the 
United States are P. davisii and P. 
duplex . 
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