12 8 AN A ceo UNT OF BRITISH FLIES. 



By this means alone will a satisfactory separation of the species of 

 MycetophilidcB be accomplished. The paper from which this has 



Fig. 25. — $ genitalia = ovipositor (Legerohre) oi Phronia. 



been mainly compiled shows amply the great specific importance 

 of the structure of the sexual organs. 



Genus. — Sceptonia, Wtz. 



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 larvfe live in fungi and rotten wood. The gnats are found in 

 shady woods. 



S. nigra, Mg. 



This is a black species, about i^ to i;^ lin. in length. The head 

 is black ; the palpi testaceous ; the antennce black, testaceous at the 

 base. The anal segment and hypopygium testaceous ; the ovipositor 

 brown, with yellow lamellae. Leg? testaceous ; tarsi brown ; black 

 tips to femora ; fore tibiae 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. — Zygomym, Wtz. 



Head roundish ; proboscis short ; palpi, eyes, and ocelli as in 

 Exechia. Forehead drawn forward in a triangular shape ; head with 



