Genus Japanagromyza Sasakawa 
Japanagromyza Sasakawa, 1958: 138. 
Type of genus : Japanagromyza 
duchesneae Sasakawa, 1954 (Japan). 
Japanagromyza appears to be intermedi- 
ate between Melanagromyza and Agromyza , 
normally with only two pairs of dorso- 
centrals (most common arrangement in 
Me 1 ana gr omy z a ) and prescutellars 
frequently present (never in Melana- 
gromyza , always in Agromyza ) . The 
halter is normally pale (dark in one 
species in Australia and one in 
Jamaica) . 
The discovery from the examination of 
males of Agromyza rutiliceps that this 
species correctly belongs i n Japanagro- 
myza has necessitated a substantial 
expansion of the generic concept. 
Hitherto all known species have been 
dark, either black or with greenish 
reflections; the head characteristical- 
ly has the frons not projecting, with 
gena narrow (fig. 335). In J. 
rutiliceps , in which the male 
genitalia indicate its generic 
affiliation (see fig. 320 and fig. 336 
of J. inaequalis ) , the frons is 
reddish, strongly projecting and with 
the gena deeply extended, and there 
are 3+1 strong dorsocentrals . It 
seems possible that the largely 
yellowish species in the small genus 
known only in the Caribbean area, 
Gera t omy za Spencer in Spencer and 
Stegmaier (1973) , should also be 
included in Japanagromyza . This would 
indicate an even wider extension of 
the generic limits, but time is not 
available now for the necessary study 
of this genus to formally propose its 
synonymy with Japanagromyza . 
Japanagromyza was erected for a small 
group of species in Japan and was 
later found to be sparsely represented 
in much of the oriental Pacific area; 
five species were recorded in 
Australia (Spencer, 1977d). Twenty 
species are known in the Neotropical 
Region (Spencer and Stegmaier, 1973: 
144). In the United States, the genus 
is present with five species in 
Florida, and its range now extends to 
the west, with J. rutiliceps known in 
California, Idaho, Montana, and Utah. 
Hosts are known of four of the six 
United States species, three in the 
Fabaceae and one in the Fagaceae. The 
larva in all instances, including 
three known in Japan and the Oriental 
Region, forms a conspicuous blotch 
mine, pupating externally. The larval 
morphology has not been studied in 
detail, but the posterior spiracles 
show considerable differentiation and 
can be specifically diagnostic (see 
fig. 345, J. aequalis , and fig. 339, 
J. inaequalis , both on Vigna ) . J. 
viridula is a well-known leaf miner on 
Quercus , and recently specimens have 
been reared from introduced Castanea 
mollissima (Chinese chestnut). 
Unfortunately no larvae or puparia of 
specimens from oak are available for 
comparison with those from chestnut 
(fig. 334), but it is here accepted 
that only a single species is involved. 
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