THE BIBIONID. 161 
i vulgaris, Mg. 
D. spinatus, Mill., W1k. 
Dilopus febrilis, Linn. (the Fever Fly) = ; D. nigritus, Oliv. 
D. forcipatus, Lat. 
|Z. 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 9 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 3 lin. 
Fic. 35.—Dzélopus 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” (Had. 
MSS.). 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 /ive 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 
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