Fever Fly Dilophus febrilis

Fever Fly
Fever Fly
Fever Flies
The Fever Fly is any of those in genus Dilophus but particularly D. febrilis, the most common in the UK and prevalent throughout the country from March to August/September.
Fever Fly male
Fever Fly female
Fever Flies
It is an elongated, black and hairy fly, 4-8mm long. Males have large eyes/heads, thin bodies, black legs and a black spot (stigmata) on each of the clear wings. Females have fuller bodies, tiny heads/eyes and dark wings with a transparent tip. (Since the male shown above left has brown legs, it may be another Dilophus species than the others on my London kitchen wall/window?)
Fever Fly
Fever Fly
Fever Fly
Larvae eat plant roots. These males have brown legs, so are likely another Dilophus species. They were in north Germany in early March.
St Mark's Fly female The related St Mark's Fly above (also called March Fly, both because they emerge in late March close to St Mark's Day) is in genus Bibio, usually species Bibio marci. It looks similar but is hairier, larger (12-14mm) and the female has smoky wings (the male has clear wings). They fly from late March to June.