52 
THE DIPTERA OF THE BRISTOL DISTRICT. 
Cecidomyid^e — The Gall Gnats. Beautiful little gnats with long 
verticillate antennae and delicate, minutely-hairy wings. The larvae 
live in vegetable galls. Asexual reproduction has been observed 
in some species. 
Cecidomyia destructor (Say) V.R.P. This is the notorious Hessian 
fly of wheat. 
,, nigra (Mg. ) C.J.W. Bred from young pears. 
brassiccE (Winn.) S.M. Common, forms swellings on 
cabbage and turnip. 
urticce (Perris) Forms galls on nettles. Common. 
cursaria (Bremi) Galls on leaves of Ground Ivy. Com- 
mon. 
veronicce (Vallot) V.R.P. Gall on stems of Veronica. 
, , crategi (Wtz.) Bristol. Common, on shoots of Haw- 
thorn. 
,, galii (Lw.) V.R.P. On stems of Galium. 
, , persicarice (L.) Bristol. On leaves of Polygonum. 
,, serotina (Winn.) V.R.P. On shoots of Hypericum. 
,, tilicE (Schr.) Bristol. Common, on shoots of Lime. 
,, ulmarice (Bremi) Common, under leaves of Spirea 
ulmaria. 
Diplosis tritici (Kirby) C.J.W. The Wheat-midge. 
,, callida (Wtz.) V.R.P. In seed capsules of Poppies. 
Hormomyia fagi (W'&xt) V.R.P. On Beech. 
,, corni (Gir.) Leigh Woods, on leaves of Cornel. 
Epidosis longipes (Lw.) V.R.P. 
Asphondylia genislce (Lw.) Bristol. Galls on Genista tinctoria. 
Lasioptera rubi (Schr.) Bristol. From galls on Rubus, emerge in May. 
Mycetophilidje — The fungus-gnats. Graceful little gnats with 
spurs on their legs ; the veins of the wings are more elaborate than 
in the Cecidomyidae, the wings are rarely hairy. Some appear in 
winter, many hibernate in hollow stems of Umbelliferae, &c. Larvae 
in fungi or decaying vegetation. 
Sciara thomce (L.) S.M. In May. 
,, carbonaria (Mg.) Bristol. May. 
morio (F.) S.M. May. 
,, prcecox (Mg.) V.R.P. 
pulicaria (Mg.) Bristol. In February. Larvae in rotten wood. 
Epidapus scabiei (A. D. Hopkins). This minute gnat has a wingless 
female, and two forms of the male, one small-winged and one 
large-winged. I bred these from decaying Narcissus bulbs at 
Clifton. The males are much more numerous than the females. 
The only previous record or description of this insect is given by 
Mr. A. D. Hopkins, 1 who found them in potatoes, " causing 
something like potato scale." Mine were in bulbs attacked by 
^roc. Ent. Soc. Washington, Vol. III., p. 149. 
