﻿THE ENTOMOLOGICAL MAGAZINE Vol. IE. 



143 



Abdomen distinctly ridged on the sides. 



Type ― Syrphus aegrotus F. 



We have in Formosa only one species. 



1. Dideopsis aegrotus F. (Pi. vi, fig. 4, 4^0 



Syrphus aegrotus F. Syst. Antl. p. 243, 48 (1789). 

 Syrphus fascipennis Macq., Suit, a Buff. I. 537. 9. (1834). 

 Didea EUenriederi Dol. Nat. Tijdschr. Ned. Ind. XIV. 407, PI. 



10， fig. 2 (1856). 

 Didea aegrota Sack. Ent. Mitt. 11. Nr. i, Fig. i. p. i (1913); 



Mats. Thous. Ins. Jap. Addit. Vol. 11, p. 215. PI. XVI, fig. 28 



(1916). 



Black, shining. Front in the male dark blue, black pubescented ； face 

 pale yellowish , giajnsh white pubescented, in the middle with a fuscous 

 stripe ； oral margin fuscous, in the female vertex and front black. An- 

 tennae brown, the 3rd joint beneath and the arista yellowish. Thorax 

 long yellowish pubescented, in the disk short fuscous pubescented, before 

 the wing-insertion on the pleura witii a vertical grayish stripe. ScutellLm 

 yellow, black pubescented, on the sides with yellowish hairs. Wings 

 hyaline, in the middle with a broad black band, at the base yellowish. 

 Abdomen black, with 3 yellowish bands, the first band being interrupted 

 in the middle, black pubescented; venter yellow, with 3 black bands, the 

 5th being entirely black. Lee's black, the anterior 4 legs, except the 

 coxae, trochanter and the bases of the femora, yellow. 

 Length — c/' ^ II-13 mm. 



Hab. ― Formosa (Horisba, i^oshun) ； China, Java, Sumatra, Phil. 



Betasyrphus Mats. (n. g.) 



Head semispherical, somewhat broader than the thorax. 丁 he facial 

 tubercle somewhat higher than the antennal-process. Antennae large, 

 the 3rd joint conical, not compressed, much longer than the 1st and 2nd 

 taken together; the arista nearly as long as the antenna itself, on the 

 outer side of the back near the base. Compound eyes strongly pubes- 

 cented; ill the male vertex much elevated and much shorter than the 

 touched portion of the compound eyes ； in the female vertex as wide as 



