FUNGUS GNATS OF NORTH AMERICA. 25 1 



eral I have refrained from naming specimens represented by 

 females alone. 



The wing venation is usually not described but instead pho- 

 tographic reproductions are given of most species. The term 

 metatarsus for convenience is retained to designate the first 

 tarsal joint though its use in this sense is etymologically incor- 

 rect. To avoid unnecessary repetition some of the statements 

 made in the synoptic tables of genera and species are not re- 

 peated in the description and hence it will be necessary to con- 

 sider the characters given in the keys, in the tables of leg meas- 

 ures, together with the figures of wing and hypopygium and 

 the diagnosis of the species, combined as constituting the de- 

 scription. 



Following the description of a species is given in brackets 

 the initials of the collector: J.M.A., (Prof. J. M. Aldrich) 

 J.B.. (Prof. John Barlow); J.C.B., (Prof. J. C. Bradley) 

 C.W.J., (Mr. C. W. Johnson) ; J.G.N., (Prof. J. G. Needham) 

 W.M.W., (Prof. W. M. Wheeler). 



Nomenclature. The arrangement of genera given here is 

 practically the same as that adopted by me in Genera Insecto- 

 riun Fasc. 93, to which the reader is referred for the synonymy. 

 It may be well to state that in this work several of Rondani's 

 genera were recognized which necessitated a few changes ; thus 

 Rondaniella was substituted for the Leia of Winnertz, Xeiira- 

 tclia for AnacVnia, Leia for N eoglaphyroptera, while Brachy- 

 canipta was united with Allodia. 



Economic relations. As far as known all of the species of 

 this subfamily pass the earlier stages in mushrooms or decay- 

 irg wood. The larvse of several species of Excchia and of 

 Mycetoph'la are occasionally found in cultivated mushrooms, 

 M. punctata quite frequently. This species is also particularly 

 common in wild mushrooms, at times very few plants escaping 

 infestation. Mushroom growers need expect but little trouble 

 from these pests if they will provide their cellars with fine mesh 

 wire screens. 



The early stages have been briefly characterized in the intro- 

 duction to Part I. Descriptions of the larvae of various species 

 and their habits are reserved for publication elsewhere. 



