8 T. OKADA 



Family DIASTATIDAE 



Key to Genera 



i Mesopleura with bristles. Orbitals above the middle of front .... 2 



- Mesopleura bare. Orbitals at the middle of front. Arista pubescent. Anterior 



reclinate orbitals slender. Subcosta short, not reaching costa 



CAMPICHOETA Macquart (p. 10) 

 2 Three orbitals present, anterior reclinate orbitals strong, posterior reclinate orbitals 

 slender. Arista with short branches. Subcosta short, not reaching costa 



DIASTATA Meigen (p. 8) 



- Only one orbital present, strong and reclinate. Arista with long branches both 



dorsally and ventrally. Subcosta complete, reaching costa 



APSINOTA van der Wulp (p. 11) 



DIASTATA Meigen 

 Diastata Meigen, 1830 : 94. 



Type-species : Diastata vagans Loew, 1864 : 362 (Europe). 



Key to Species 



1 Wing with two large transverse black bands surrounding crossveins. C-index about 



32 .......... ussurica (p. 8) 



- Wing black only at its base and along posterior crossvein, fuscous along costa. 



C-index about 60. . . . . . . . . . basdeni (p. 8) 



Diastata ussurica Duda 



Diastata ussurica Duda, 1934 : 8 (Ussuri) ; Okada, 1956 : 13 (Japan) ; Okada, 1960b : 165 

 (Japan). 



cj. Wing patterns somewhat intermediate between those of Ussurian (Duda, 1934) 

 and Japanese (Okada, 1956) forms, the black patch covering posterior crossvein 

 distinctly narrowing below M as in the Ussurian form, but extending outside 

 posterior crossvein as in the Japanese. 



Taplejung District, below Sangu, mixed vegetation on sheltered slopes above river, 

 c. 4,000', 3.1.1962, 1 $ (R.L.C.). 



Distribution : Nepal (new locality), Japan, Ussuri. 



Diastata basdeni sp. n. 



(Text-figs. 12-15) 



$. Body about 3-5 mm., black, slender. Head much broader than thorax. Eyes dark 

 purplish red, bare. Antennae orange-yellow ; third segment broad, slightly more than twice 

 as long as broad, apical half fuscous, anteroventrally narrowing. Arista black, shortly plumose 

 on both sides. Palpus slender, curved, yellow, basally brown, with about three black setae near 

 apex below. Ocellar triangle fuscous. Periorbit fuscous, strongly curved inward anteriorly, 

 ending before middle of front. Front pale yellow, anterior margin concave, anteriorly slightly 

 broader than length down middle, posteriorly half as broad as head width. Face pale yellow, 

 shining silvery white in dorsal view. Carina undeveloped, represented by a weak median ridge. 

 Cheeks yellowish grey, about two-ninths the greatest diameter of eye. Postgena black. Clypeus 

 reddish brown. Occiput black, concave, grey pollinose. Anterior reclinate orbital longer than 



