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Ä 蟲 舉雜篛 第 Ä 卷第四 IK 



the half breadth ot the iront between the antennae. Proboscis moderately 

 long, not longer than the height of the head, the palpi very small ； oral 

 opening oblong. Wings moderate, the 3rd longitudinal vein straight, 

 opens near the apex, the cross-vein near the base, at about of the 

 discoidal cell, the bend of the 4th longitudinal vein with a lonp- appendage. 

 Abdomen on the sides scarsely ridged. 7 his genus resembles somewhat 

 to Ischyrosyrphus Big., but the 3rd antennal joint much differs from 

 the latter. 



Type ― Syrphus serarius Wied. 

 We have in Japan the following only one species. 



Betasyrphus serarius Wied. (pi. iv， fig. 6,6".) . 

 Syrphus serarius Wied - 、 Auss. Zweifl. II. p. 128， 20 (1830)； Schin. 

 —Dipt. Nov. Reis. p. 352. 37 (1868); CoQ. 一 ProcNat. Mus. U.S.A. 

 XXI, p. 321 (i8q8^; Matsum. — Thous. Ins. Jap. Vol. II. p. 94, 

 PI. XXV, fig. 14 (1904); Sack — Ent. Mitt. II， p. 5 (1913)- 

 Dark brown. Face pale fulvous, with a fuscous stripe, which not 

 reaches to the antennal-insertion, fuscous pubescented ； cneeks and oral 

 margin grayish fuscous ； the antennal-process (except the apex which is 

 yellowish), front and vertex dark bluish, in the female the front on the 

 sides and in the middle yellowish pruinose. Antennae fuscous, the 3rd 

 joint beneath and the base of the arista yellowish. Compound eyes in 

 the male brownish and in the female whitish densely pubescented. Occi- 

 put dark bluish, fulvous pubescented. Thorax brownish or bluish black, 

 with 3 fuscous stripes, pale yellowish long- pubescented, on the sides 

 yellowish. Scutell.um dirty yellow, with some waxy luster, long black 

 pubescented, on the sides yellowish. Scutellum dirty yellow, with some 

 waxy luster, long black pubescented. Wings hyaline, with a light brown- 

 ish tinge, stigma dirty yellow, veins fuscous. Calyteres pale yellowish. 

 Kälteres fuscous, at the apices yellowish. Abdomen black, with 3 narrow 

 bands, the first band bluish, the 2nd and 3rd dirty yellow, black and 

 yellowish pubescented. Venter shining grayish, with 2 silvery bands, in 

 the female each segment in the middle with a fuscous spot. Legs pale 

 brownish, coxae, trochanter and the basal halves of the femora fuscous. 

 Length ― ^ 1 1 一 12 mm. 



