THE BIBIONID^. 



t6i 



D. vulgaris, Mg. 



D. spwatus. Mull., Wlk. 



Dilopus febrilis, Linn, (the Fever Fly) = [ D. nig?-ifiis, Oliv. 



\D.forcipatus, Lat. 

 \T. marci, Schk. 



As this is one of our so-called insect pests, we deal at greater 

 length with this species. The imago is black; (^ shining black; 

 eyes hairy ; proboscis and palpi blackish. Wings whitish, brown 

 along the costa, and the stigma blackish ; veins near the costa black ; 

 remainder white. Abdomen quite black. Legs black ; tibia at its 

 base armed with a circular row of thick spines, one very large. The 

 edge of the tibia has also a pair of spines and one single one deve- 

 loped on the anterior legs ; femora hairy and broad in the anterior 

 legs, narrow in the posterior ; metatarsi short, second and third tarsal 

 joints small, with a few large bristles ; last joint long and rounded 

 at the tip, finely hairy ; ungues long and dark ; pulvilli three and 

 yellowish, the edges apparently striated. The $ has blackish-brown 

 wings, paler along the hind border ; stigma and veins almost black. 

 Eyes not contiguous, as in the (^ . Abdomen brown. Length 

 2 to :: lin. 



Fig. 35. — Dilopus febrilis. — The Fever Fly. 

 (From Miss Ormerod's Manual Inj. Ins.) 



Walker says concerning this species that it is generally distributed 

 " in profusion everywhere — most so on sandhills. Appears in con- 

 servatories even during a severe frost in the middle of winter " {Hal. 

 JlfSS.). This latter statement I cannot verify. It is a common 

 insect at my home (Kingston-on-Thames), and large numbers 

 appear in the grounds and conservatories ; but although I have 

 often searched for them in winter I have not been successful in 

 finding any live specimens later than November or the first week in 

 December. Lots may often be found at all times in the cobwebs. 

 In grape-houses they seem particularly abundant. This "fever fly," 

 which is two-brooded, occasionally appears in vast swarms. " It 



