REMARKS ON COLLECTING DIPTERA.
89
to the Tachinidae (Dexia). (3) Sarcophagidae The females are
viviparous ; the species very closely allied. Several are common,
Sarcophaga carnaria being the most abundant, breeding in decaying
animal matter of every description. (4) Muscidae, These are the
most typical of all the Diptera, and are the greatest natural scaven-
gers of the order. About thirty species are British, many being very
common (Lucilia; Musca). (5) Anthomyidae. A few are leaf-miners.
Over 200 species are British, many being common and generally dis-
tributed in woods and fields. The smaller species may be obtained
in abundance by "sweeping" (Hyetodesia; Anthomyia; Chortophila).
(6) Acalypterata. Small flies, sombre in colour, and closely allied,
divided into nearly thirty groups. About 500 species are British,
many being common. They occur chiefly on grass-covered ditch
banks, and on plants, a large number of species being leaf-miners
(Borborus; Scatophaga; Chlorops; Agromyza; Trypeta; Sapromyza).
PhoridAe.—Small brownish flies, allied to the above group, easily
distinguished by the venation. Phora rufipes, a ubiquitous species,
feeds in the larval stage on nearly everything, and is common in
London.
I have arranged the sequence of the families in accordance with
Verrall's list, but have omitted the Pulicidae (Fleas) which do not
appear to me to be true Diptera.
The following species have been taken by me in Epping Forest,
but it is not to be supposed that this list represents more than a small
percentage of the species probably occurring there, and in fact con-
sists merely of the species that have fallen to my net on the three
occasions on which I visited the Forest.