42 Syrphidae. 



of the discai cell; cubital vein nearly straight; upper marginal cross- 

 vein recurrent above and retracted from the margin; no stigmatical 

 cross-vein. 



The larvæ are scavengers in the nests of Vespa and Bombus; 

 they are flattened. 



Only one Danish (and European) genus 28. Volucella. ^fy 



III. Eristalinae. 



Antennæ short or of moderate length, drooping, arista bare, 

 pubescent or distinctly pliimose. Epistoma with a small central knob 

 or with none, in a single case conically prolonged; its ground colour 

 is black or yellow with or without middle stripe, but it is generally 

 densely pruinose, and it is hairy. Eyes in the male touching or 

 separated, but less than in the female. Subcostal cell open or closed ; 

 medial cross-vein at or after the middle of the discai cell; cubital vein 

 with a deep loop down into the first posterior cell; a stigmatical 

 cross-vein present or indistinct or wanting. Hind femora often thickened 

 and hind tibiæ more or less compressed and curved. 



The larvæ belong to the rat-tailed type; they live in putrid water 

 or in humid hollow trees; Merodon makes an exception, it is some- 

 what similar to a Si/rphus-\arva. and feeds in bulbs of Narcissus. 



Table of Genera. 



1. Subcostal cell closed 29. Eristalis. T f:>\ 



— Subcostal cell open 2. ' 



2. Hind femora with a tooth-like process beneath near apex 33. Merodon. -f J(^ 



— Hind femora without any tooth-like process beneath 



at tip 3. 



3. Eyes hairy, touching for a distance in the male 31. Myiatropa. -f-h'j 



— Eyes bare, separated in the male, or only touching in 



a point 4. 



4. Eyes separated in both sexes ; thorax with longitudinal 

 pale stripes; body not much hairy; hind femora with- 

 out a dense clump of hairs beneath near apex 30. Helophilus.^-fÆ^ 



— Eyes touching in a point in the male; thorax unicolorous, 

 densely pilose; hind femora with a clump of hairs on 



a small swelling beneath near apex 32. Mallota. y^ "7 2_ 



IV. Milesiinae. 



Antennæ short or slightly elongate, not distinctly porrected, though 

 often only moderately drooping, arista bare or long-plumose {Are- 



