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昆蟲學 雑誌 第 iSC 卷第四 



に Vertex in the female broader than the half breadth or the iront 



between the antennae 9 



一 Vertex in the female much narrower than the half breadth of 



the front between the antennae Episyrphus n.g. 



6. Ihe lower part of the face in the male beak-like produced ... 



, Stenosyrphus n.g. 



^ The lower part of the face in the male not beak-iikc produced. 

 ••• Mesosyrühus n g. 



7. The 3rd antennal joint strongly compressed ； the cross-vein at 



about of the discoidal cell... … Syrphus F. 



一 The ヌ rd antennal joint not compressed ； the cross-vein at about 



of the discoidal cell 8 



8. The arista near the middle of the 3rd antennal joint on its back; 



head and front not very large Metasyrphus n.g. 



一 The arista near the base ； head and front very large.... 



Catabomba Ost. 



9. The arista near the base; the 3rd longitudinal vein straight ... 10 

 一— The arista near the middle ； the 3rd longitudinal vein strongly 



curved into the first posterior cell Didea Macq. 



10. The 3rd antennal joint compressed ； the arista much longer than 



the antenna itself ； the bend of the 4th longitudinal vein with- 

 out appendage (only a fold may be seen) … Dideodes n. 

 ― The 3rd antennal joint not compressed or only on the back 

 compressed ； the arista nearly as long as the antenna itself ... 1 1 



11. The 3rd antennal joint not compressed, long conical ； the bend 



of the 4th vein with appendage Betasyrphus n.g. 



一 The 3rd antennal joint on its back compressed, short blunt 

 conical ； the bend of the 4tlT»vein without appendage (only a 

 fold may be seen) Bideopsis n.g. 



Asarcina Macq. 

 Macquart — Dipt. Exot. 11， pt. i, p 137, 1840. 

 Ancylosyrphus Bigot, 1882. 

 Proboscis narrow and long, somewhat longer than the height of the 

 head, palpi small ； oral opening narrow, in the middle being constricted. 



