154 STKPHID^. 



open ; anterior cross-vein at one-third of discal cell ; 3rd vein 

 nearly straight. Whole venation like that of Chilosia, though 

 the tip of the 4tli vein is just appreciably recurrent: lialteres dull 

 yellowish. 



Length, 11 mm. 



India : redescribed from the unique type in the Bigot collec- 

 tion, which is in inferior condition but has the generic and 

 specific characters sufficiently obvious. 



Subfamily ERISTALIN^. 



Antennae moderately long, pendent, arista dorsal, bare to 

 plumose. Wings with anterior cross-vein at or beyond middle 

 of discal cell ; 3rd vein with a distinct downward loop into 

 1st posterior cell ; marginal cell generally open except in Eristalis 

 (s. lat.). Hind femora usually thickened and often with a distinct 

 subapical dilatation or with a tooth-like process. 



This subfamily is of world-wide distribution, the two principal 

 genera Eristalis and Helophilus (one or the other, generally both) 

 having representatives in every quarter of the globe; but in 

 several of the genera the species are very closely allied, and more- 

 over often subject to considerable vai'iation, which makes a keen 

 study of allied species a sine cpia nonior their certain identification. 

 Even the European species of one of the largest genera, Merodon, 

 are but imperfectly understood. 



The life-histories of some forms have been unravelled; the larvae, 

 except those of Merodon, are usually of the "rat-tailed" type, as 

 in the common Eristalis tenax. In some species the apical promi- 

 nence in the larva forms a flexible tube capable of extension to 

 several times the length of the body. Many species are excellent 

 hoverers and nearly all are of general distribution, preferring sun- 

 shine, open spaces in woods, flowering or sweet-smelling plants 

 and bushes. One or two species of Helophilus extend to the 

 Arctic regions. 



Tahle of Genera. 



1. Marginal cell closed 2. 



Marginal cell open 5. 



2. Hind femora toothed Priomerus, Macq., p. 155. 



Hind femora not toothed * 3. 



3. Thorax broader than long ; scutellum 



abnormally wide ; a wrinkled space 



on frous above antennne Megaspis, Macq., p. 196. 



Thorax quadrate ; scutellum of normal 

 shape ; no wrinkled space on frons . . 4. 



4. Anal vein elongate, tip recurrent (much 



as in Milesi(i) ; loop of 3rd vein 



diagonally placed Korinchia, Edw., p. 224. 



Anal vein not elongate, often barely 

 reaching margin of wing; loop of 

 3rd vein normal Eristalis, Latr.. p. 155. 



* Except in Megaspis crassus, Fabr. 



