﻿140 



昆蟲 舉雜誌 第5^卷第四？虎 



hairs, those on the nrst 2 segments very long, nearly to the middle oi 

 the 2nd segment yellow. Venter yellow, the black bands of the dorsum 

 being visible through. Hypopygium small and very shining." 

 Length 一 ^. 13 mm. 



Hab. ― Formosa (Taikokan) ； China, Sumatra, Ternate, Ceram, 

 Waigoe. 



The above description was made by Dr. P. Sack in the paper "Entom- 

 ologische Mitteilungen" II. Nr. i. p. 2 (1913). From the description it 

 may not be a true Dldea, and "it may belong probably to my genus 



Dideodes. 



Dideodes Mats. (n. g.) • 

 Differs from Bidea Macq. as follows : 



The 3rd antennal jomt compressed, as long as the first and 2nd taken 

 together, near the base at the back with a long arista, which is much 

 longer than the antenna itself. Proboscis much longer, nearly % of the 

 height of the head, oral opening oval, narrower towards the apex. 

 Vertex (^) much narrower than the half breadth of the front between the 

 antennae. Compound eyes pubescented. Wings broader and longer, 

 , the 3rd longitudinal vein opens before the apex, nearly straight or a 

 little curved, the cross- vein at about \ of the discoidal cell, the bend of 

 the 4th vein without appendage (only a fold ifiay be seen). The lateral 

 sides of the abdomen distinctly ridged. 



Type 一 Syrphus latus Coq. 

 We have in Japan and Formosa the following- 3 species. 



Table of Species. 



1. Scutellum and abdomen black lautus CoQ. 



一 Scutellum and abdomen yellow 2 



2. Scutellum yellowish pubescented latus Cog. 



一 Scutellum brownish pubescented formosanus Mats. 



1. Dideoides latus Coq. (p】. VI， fig. 3, 3 a. ) 

 Syrphus latus Coq., Proc. Nat. Mus. U.S.A. XXI， p. 322 (1898); 



Mats., Thous. Ins, Jap. Vol. II. p. 87, PL XXV, fig, i (1904) 

 Yellow ； meson otum fuscous, in the male aeneous, shining^. Face 

 yellow, yellowish pubescented, vertex and upper part of the front black, 



