I9I4-] B. Brunettt : Review of Genera in Culicidae. 23 



as good genera^ whilst the somewhat lesser modifications exemplified 

 in Megarhinus and the Sabethini are also constant inter se. 



The Scales. — There is no analogy in other families of 

 diptera respecting classification by the scales which clothe the 

 greater part of the body, legs and wings in nearly all Culicidae, 

 and Theobald may be regarded as the pioneer of a classification 

 built mainly on this character. 



An exhaustive examination of the scales is however un- 

 necessary here, since to any unbiassed examiner it must soon 

 become obvious that any serious attempt at classification of 

 genera on this character alone is foredoomed to failure. 



The continual shifting of species from one genus to another, 

 according to the views of each writer, and of the same author 

 at different periods, illustrates on what a slender basis such a 

 classification rests The difficulty of deciding the exact shape 

 of the scales, the quantity of them requi>ite to throw a given 

 species into one genus or another, and their exact surface 

 distribution ; in each case according to each writer's interpretations 

 of other authors' impressions, as well as to those of his own, is 

 self-evident at the outset. Even mosquito workers themselves 

 are admitting this difficulty. 



Scale characters are admittedly useful in sorting species into 

 groups, but it is impossible to regard these even as subgenera 

 on account of the presence of so many intermediate forms. 



More recently still, Mr. Edwards says (Bull. Ent. Res. iii, 3), 

 " scale characters have practically^ been discarded as of value in 

 generic definition," and it must be admitted the general tendency- 

 is in this direction. Col. Alcock regards them as quite unsatis- 

 factory, Edwards sinks wholesale, genera so made, and Felt and 

 Dyar and Knab consider genitalic and larval structure as of higher 

 value. One or two recent authors place the construction of the 

 claws before the scales. Only when scales or chaetae, or both to- 

 gether are present on the metanoium, a part of the body normally 

 unadorned in diptera, at least with anything stronger than pubes- 

 cence, can they be regarded of generic importance. In my paper 

 on taxonomic values ' I underrated their systematic importance 

 when on this part of the body, and the Sabethini section are suffi- 

 ciently differentiated by this character alone. 



As regards scales on the legs, these afford no assistance 

 beyond specializing two or three genera [Psorophora, Mucidus, 

 Lophoscelomyia) in which their length and outstanding nature give 

 the insect a ragged appearance. Yet tufts or fringes of long out- 

 standing scales are found on the legs of several species of Empis, 

 in some Bombylidac {Hyperalonia, Exoprosopa) and in other genera 

 in diptera without such species being accorded thereon generic rank. 



The Claws.— Theobald at first (Monog. i, ii) attached much 

 value to the claws and Coquillett still does so (Can. Ent. 1876, 

 p. 43, and Science xxiii, 313—1906) but the former admitted later 



1 Rec. Ind. Mus. iv, 53. 



