DIDEA. DIDEOIBES. O / 



Legs : coxse black ; anterior femora orange, basal third black, the 

 colour extended a little on middle p;iir : anterior tarsi black. 

 Hind legs black, except tips oF femora narrowly orange. Pubes- 

 cence black, orange on anterior tibia;. Wings nearly clear, sub- 

 costal Cell and stij^ma blackish ; 3rd vein considerably looped down- 

 ward into 1st posterior cell; squama; pale yellow with deeper 

 margius. IJalteres brown, tip of knob orange. 



Length. 12 mm. 



The above description is abbreviated from A^ei'rall as being 

 likely to be more correct, since bis description was drawn up from 

 a number of specimens ; whereas only one specimen is available 

 to me, though thei'e is practically no doubt of its identity. The 

 legs are, however, described from the unique Assam specimen, as 

 they show sliglit differences from Verrall's description; hut a $ 

 fasciata from Austria in the Indian Museum has the legs almost 

 exactly similar. 



One $ from Shillong, 5000 ft., x. 1 916 {Fletcher). In the Pusa 

 collection. The Paris Museum possesses what is probably the 

 type of the species. It ranges from Central and South Europe to 

 Japan and North America as well as to India. 



Genus DIDEOIDES, Brim, 

 Dideoides, Brunetti, Hec. Ind. Mu9. ii, p. 54 (1908). 

 Genotype, D. ovata^ Brun.; the original species. 



Allied to Dldea, Macq., from which it is separated essentially by 

 the 3rd longitudinal vein (cubital, Verrall) being nearly straight, 

 as in Sgrphus, and not dipped, as in Eristalis, into the cell below. 

 In other respects it resembles Bidea, ]\Iacq., having a bare arista 

 and the large, Hat ovate abdomen in both sexes much Mider than 

 the thorax, and bearing the distinct, ridged margin as in that genus. 



Tiiis genus has appeared to me unstable at times, as the species 

 referred to it form a transition from true Didea to Sgrphus. 

 Theoretically Didea should possess the following four characters : 

 a ridged edge to the abdomen, a definitely dipped 3rd vein, bare 

 or nearly bare eyes and all-black antennae. I), fasciata of course 

 possesses them all. I placed annandalei in Didea because of the 

 quite bare eyes, and disregardful the barely dipped 3rd vein as of 

 minor importunce, but if the scope of Dideoides be widened to 

 include both bare- and pubescent-eyed species, the genus can 

 include this species. 



Didea therefore essentially differs from Syrplius (apart from its 

 general facies) in the ridged abdomen and the conspicuously 

 dipped 3rd vein, as tlio bareness of the eyes and the all-black 

 antennie appear unreliable characters. 



Dideoides differs from SgrpJurs only in the ridged abdomen, and 

 from Didea only in the nearly straight 3rd vein. The five species 

 now- retained in it are truly congeneric and possess the orthodox 

 facies of Didea. 



