56 . SYRPHID^. 



Genus DIDEA, Macq. 

 Didea, Macquart, Hist. Nat. Dipt, i, p. 508 (1834). 

 G-E>'OTYPE, Didea fasciata, Macq. ; by original designation. 



Very near Syrphus, but differing by the 3rd vein having a 

 distinct downward bend into the 1st posterior cell, somewhat 

 resembling its course in Eristalis. Eyes very nearly bare. An- 

 tennae proportionately rather larger. Abdomen quite oval, flattened, 

 broader than thorax, with the extreme margin distinctly raised 

 and black, except where the yellow spots overlap the side margins. 

 In all else practically as in Syrphus. 



Only one species, which is widely distributed, is Oriental. 



Range. Europe, India, Japan, North America. 



45. Pidea fasciata, Macq. (PI. I, fig. 15.) 



Didea fasciatu, Macquart, Hist. Nat. Dipt, i, p. 508 (1834). 

 S $ . Head : frons dusted with yellowish-grey, often with a 

 large blackish spot above each antenna ; pubescence rather long, 

 mainly black; vertex elongate, shining blue-black, with short black 

 pubescence. Eyes slightly pubescent. Antennae dull blackish, 

 3rd joint large, twice as loug as 1st and 2nd together ; arista 

 brown, bare. Face shining yellow, nearly bare of dust, but with 

 rather abundant pale yellow pubescence ; front of mouth-border 

 brownish. In $ , frons at upper part, just below antennae, con- 

 siderably more than one-third of head, shining blue-black at vertex ; 

 side dust-spots near middle joined to dust of face, leaving a more 

 or less complete black stripe to the large black lunule above the 

 antennae. Thorax shining greenish-black, two rather faint, 

 moderately broad, greyish stripes on anterior part, narrowly 

 separated. Pubescence moderately dense, tawny; longest on side 

 margins and on the whitish-grey pleurae. Scutellum brownish- 

 yellow with yellow tip seen from above, or orange with blackish 

 basal corners if seen from the side ; pubescence tawny, some long, 

 thin black hairs round margin. Ahdoraen black, a pair of large 

 irregularly oval orange spots on 2nd segment, placed rather 

 diagonally from front half of side margin towards middle of liind 

 border, but their inner ends well separated and not attaining hind 

 border; 3rd segment with an orange band placed not quite on 

 front margin, narrowly clear of side margins and well clear of 

 hind margin, its hinder side deeply cut away in middle ; -Ith seg- 

 ment with a pair of elongate triangles, placed clear of all margins, 

 their apices meeting in the middle line. In $ , a pair of spots on 

 anterior coi-ners which sometimes meet in the middle line, and 

 the band on the 2nd segment sometimes attaining side margins. 

 Entire margin of abdomen narrowly raised in both sexes ; pubes- 

 cence of margin wholly black except ^here the side margins are 

 yellow, in Avhich parts it also is yellow ; pubescence on disc 

 following ground-colour. Genitalia black, with yellow pubescence. 



