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A KEY FOR DETERMINING THE AFRICAN SPECIES 

 OF ANOPHELES (SENSU LATO). 



By F. W. Edwards, B.A., F.E.S. 

 (Published by permission of the Trustees of the British Museum). 



The compilation of the following key has been a matter of no little difficulty, 

 mainly owing to the close connection of the species in some of the groups, which 

 sometimes makes it almost impossible to assign specific limits. The difficulty has 

 in some cases been increased through the paucity of material, which prevents any 

 adequate conception of the range of variability being obtained. This is particu- 

 larly the case with some of the species coming from the Mediterranean region, 

 which are very closely allied, and of which, as a rule, the British Museum 

 possesses very few specimens. Names have only been sunk here as synonyms in 

 those cases where there appeared to be no reasonable doubt, either after a com- 

 parison of the types, or of the descriptions, when these were sufficiently detailed. 

 Eventually, therefore, it may be found that some forms which are here given 

 specific rank will have to be regarded at most as varieties. Since so many 

 figures of Anopheline wings, etc., have already appeared, it is not deemed 

 necessary to add to their number. Some new records have been included, but on 

 the other hand some old ones, which appeared to be questionable, have been 

 omitted. As with the writer's previous papers, this key is merely intended to 

 supplement the detailed descriptions which will be found in other works. 



The recent subdivisions of the old genus, proposed by Mr. Theobald, have been 

 discarded, since they grade imperceptibly into one another, and are not founded 

 on any structural differences, while Anopheles in the broad sense is a very well- 

 defined genus easily recognisable even by an amateur. It is sometimes argued 

 that certain species are more and others less closely related, and that it is 

 necessary to give expression to this obvious fact in our nomenclature, by the 

 employment of a generic or subgeneric name for each group. But such a course 

 appears to me to be quite unnecessary, and to tend merely to obscure larger 

 relationships, while it greatly increases the difficulty of determination. In 

 the proposed " genera " of Anophelines the characters relied upon are 

 not only most trivial, but are sometimes variable within specific limits 

 {e.g.) " Pyretoplwrus " costalis), and may be confined to one sex. It is quite 

 possible, too, that genera founded on such superficial characters as the width of 

 the scales might prove to be polyphyletic. The differences found in the larvae, 

 like those between the adults, are very slight, and moreover they do not seem to 

 support the classification by scale characters. 



The leading characters of the key will serve to indicate the approximate 

 limits of such of these so-called genera as are African, but as Lt.-Col. Alcock 

 has shown us, # they cannot be clearly distinguished — except perhaps Nyssor- 

 hynchus [= Cellia] and Christy a, both of which have well-marked lateral scale- 

 tufts, but entirely different in character, while the latter has no scales on the 



* Ann, Mag. Nat, Hist. (8) viii, 1911, pp. 240-247, 



