128 AN ACCOUNT OF BRITISH FLIES. 
By this means alone will a satisfactory separation of the species of 
Mycetophilide be accomplished. The paper from which this has 
Fic, 25.— 2 genitalia = vipeniiae (Legerodhre) of Phronia. 
been mainly compiled shows amply the great specific importance 
of the structure of the sexual organs. 
GENuS.— Scepionia, Wz. 
_ This is a small, dark-coloured genus. -The middle tibia has one 
row of black spines on its inner surface. The costa passes beyond 
the apex of the third longitudinal. The anal is incomplete (sixth), 
and the seventh longitudinal vein is very long. 
The larve live in fungi and rotten wood. ‘The gnats are found in 
shady woods. 
S. nigra, Mg. 
This is a black species, about 1} to 14 lin. in length. The head - 
is black ; the palpi testaceous ; the antennz black, testaceous at the 
base. The anal segment and hypopygium testaceous ; the ovipositor 
brown, with yellow lamelle. Legs testaceous; tarsi brown; black 
tips to femora ; fore tibize longer than fore metatarsi. Wings yellowish 
or with a brownish-yellow tinge (Walker describes them as gray). 
This fly appears in woods and thickets fairly plentifully from April 
to October. 
GENUs.—Zygomyia, Wtz. 
Head roundish; proboscis short; palpi, eyes, and ocelli as in. 
Exechia. Forehead drawn forward in a triangular shape ; head with 
