CECIDOMYIDiR. 



123 



pass the winter. In England there is bnt one brood, that 

 of early summer, and the fly is not nearly so injurious to 

 growing grain. 



I give two tables of the genera. The first is that of the 

 previous edition of this work with minor modifications, 

 and is nearly that of Wulp, Sehiner, Winnertz and H. 

 Loew, with additions. The figures illustrating these 

 principal groups are, for the most part, taken from Wulp, 

 and are of typical forms in the sense of Kieffer. In ad- 

 dition I give a transcription of Kieffer's table as publish- 

 ed by him in 1898 (Bull. Soc. d'Hist. Nat. Metz.), with 

 certain abbreviations, especially of those characters de- 

 rived from the structure of the genital organs, characters 

 which I view with suspicion ; and I have modified his 

 terminology in accordance with the true conception of 

 the dipterous venation, since Kieffer's terminology is 

 only a makeshift, not based upon comparative studies, 

 Some of Kieffer's genera are evidently founded upon 

 characters which would have been considered of generic 

 value by the older writers, but, for the most part, they 

 are merely permutations of what have, hitherto, been 

 considered as specific characters, and I am convinced 

 that some of them, as he defines them, are in a high de- 

 gree artificial. One should always be suspicious of char- 

 acters which permit perfectly parallel subdivisions in 

 parallel phyla, for one must be assured that the charac- 

 ters selected for primary subdivisions are not really ho- 

 moplastic and of secondary importance, and it is apparent 

 that some other writer with different views of the relative 

 importance of these characters might properly revolu- 

 tionize the whole system. Furthermore, it will be appar- 

 ent that Kieffer in some places ignores as of slight or 

 minor value characters which in other places he raises 

 to higher rank. His 'pelote unique', 'trois pelotes', 

 'crochets bifides' and 'crochets simples', as well as the 



