210 



DIPTEKA OR TEUE FLIES. 



with paraffin-oil and soap, rubbed with a sponge. Miss Ornierod 

 mentions soluble phrenyl as useful in one of her reports. 



The rest of the Hies belong to the section Oydurrhaplia, which 

 is divided again into the Pruhoscidea and Eprohoscidea. The 

 Probosoidea contain the majority of flies, the following being 

 the most important economic forms : — 



Hover-flies, or Ssrrphidse. 



The Syrphid;e are all moderate-sized flies, often brilliantly 

 coloured, generally Avitb banded bodies, yellow and black or 

 brown being the predominating colours. The}' hover in the air 

 like a hawk, suddenly darting uS. and again remaining (]^uivering 



Fin. lO.S,— HovKR-FLiKS i^Siirphidir). 



1, Syrphiifi hnJWitu^ ; 2, larva devouring apliis ; 3, pirpa ; -I, latiih^mba pijrastri; b, 

 ]arva ; li, pnpa ; 7. ^Sijrpliu.^ rlbesii. (Curtiy.) 



at a fresh spot. "\\'e only see them in the bright sun, and may 

 notice them flying and hovering over pilants, upon the nectar of 

 which the adults feed. At other times we see them busy over 

 colonies of Aphides, for here they dejiosit their eggs, their 

 curious, almost re])ulsive-looking larvfe (fig. 103, 2 and 5) feeding 

 upon plant-lice, wliich they devour with great rapiditv. The 

 larva} are yellow, green, or red in colour, with a narrow anterior 



