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見 Ä 學雜誌 第^ 卷 第寳號 



0. Hind femur somewhat thickened, with a row of bristles ... 



Eumems. 



― Hind femur not thickened, not with a row of bristles ... 



Melanostoma. 



7- Mesonotum with yellow lateral stripes 8 



一 Mesonotum not with yellow lateral stripes 9 



8. Abdomen narrow, with 7 abdominal segments, in the male 



with a projecting genital organ Melithreptus. 



― Abdomen broad elliptical, with 5-6 abdominal ； segments, 

 genital organ of the male not projecting... Xanthogramma . 



9. The third longitudinal vein strongly curved into the first 



posterior cell Didea, 



一 The third longitudinal vein straight or a little curved into 

 the first posterior cell Syrphus. 



Genus I. Chrysotoxum Meigen. 

 Me I GEN : ill Illiger's Magazine II 259 (1803). 

 Musca L. ； Conops Scop.; Mulio F. and. Fall. 

 Syrphus Panz ； Milesia F. 



A genus of quite large size, nearly bare, black, with yellow cross- 

 band on abdomen. 



Head a little broader than the thorax ； antennae longer than the head, 

 porrect forward, standing on a conical process, three joints nearly of the 

 same length, last two joints together somewhat spindle-shaped, flattened, 

 near the middle with a bare arista. 



Face broad, bare, somewhat elongated ； near the oral margin on the 

 upper side with a little tubercle. Eyes bare or hairy, in the male holop- 

 tic, ellipsoidal in the form. 



Thorax nearly quadrangular, with rounded humeri; mesonotum on 

 each side with a lateral yellow stripe. Scutellum hemicircular, totally 

 or partly yellow, with fine hairs. 



Abdomen somewhat hump-backed, broad and thick, with yellow cross- 

 bands, which are interrupted in the middle and curving towards poster- 

 iorly ； on the ventral side with yellow cross-bands. All the rings of the 

 abdomen except the last, on each side at the posterior margin with a 



