Syrphidae. 43 



tophila, Sericomyia). Frons generally prominent and generally bare, 

 sometimes a little pubescent, rarely more haired. Epistoma very 

 varying, straight and more or less flat or keel-shaped, or more or less 

 hollowed with or without central knob; in a single case {Myiolepta) 

 with a knob in the male, none in the female; it is not, or somewhat 

 to much descending, and not or more or less protruding below ; the 

 coloiir is yellow, yellow and black or quite black, but generally pale 

 pruinose, and it is bare or only slightly haired at or tovvards the 

 sides, rarely more haired. Eyes touching or approximated in the male. 

 Subcostal cell open (in all Danish genera) ; medial cross-vein at or 

 after the middle of the discai cell, generally rather oblique, only in 

 Myiolepta before the middle of the discai cell; cubital vein straight, 

 or sometimes somewhat ciirved downwards or looped ; no stigmatical 

 cross-vein or this indistinct. Hind femora in most cases thickened, 

 sometimes most in the male, sometimes strongly, and often with a 

 tooth below or with rows of spines. 



The larvæ live nearly all in decaying tree or in sap on ulcerated 

 trees, sometimes in other decaying vegetables or in dung; Eumerus 

 in bulbs of Allium; tbey are moie or less elongated oval, with a 

 short or a little longer posterior spiracular process; Pocota, Myiolepta 

 and Calliprobola (the latter not Danish) have a short tail, and they 

 have all anterior spiracular tubes in the pupa. ISericomyia has a larva 

 of the rat-tailed type, living in water in peat-bogs. 



This subfamily is scarcely quite homogenous; Arctophila and 

 Sericomyia with their long-plumose arista and hairy frons (and long- 

 tailed larva) stand apart, and the same is perhaps the case with 

 Eumerus. 



Tahle of Genera. 



1 . Arista bare 2. 



— Arista plumose 14. 



2. More or less densely and long pilose species 3. 



— Rather inconspicuously haired species 6. 



3. Hind femora without spines beneath; abdomen more 



or less ovate 4. 



• — Hind femora with spines beneath; abdomen some- ^ 



what elongate 39. Brachypalpm. J^q^ 



4. Epistoma considerably descending, somewhat pointed 



at apex, with a central knob 5. 



— Epistoma slightly descending, not pointed and with- , 

 out central knob 37. Pocota. ^<\<^ 



5. Eyes narrowly separated in the male; densely pilose ' 

 species 36. 'Criorrhina. '4 ^o 



— Eyes touching in the male ; moderately hairy species 



