23 



ON THE BRITISH SPECIES OF SIMULIUM.— I. THE ADULTS. 



By F. W. Edwards. 

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



The theories at present widely accepted regarding the connection between the 

 SiMULiiDAE and pellagra have brought this family of blood-sucking flies very much 

 to the front in recent years, and have rendered it highly desirable that accurate 

 information should be available concerning the different species, their distribution 

 and habits. It is in the hope that the facts brought forward may be of use at some 

 future time, and that the way may be cleared for further research, that the present 

 investigation has been undertaken. The writer has examined over 1,000 pinned 

 specimens, including the material in the British Museum, the Cambridge Museum and 

 the Edinburgh Museum, together with a large number of additional specimens 

 kindly lent by various private correspondents. The result of this examination will, 

 it is believed, go some way towards an elucidation of the European species of this 

 family. 



No exact work has ever been published upon the British species, and although a 

 large number of names have been applied to European forms, the descriptions are 

 for the most part unrecognisable. Recently, however, Dr. C. Lundstrom has given 

 us an account of the Finnish species.* In this paper for the first time some attention 

 is paid to the male genitalia, and a number of figures of these organs are given. 

 Lundstrom, however, has not studied them sufficiently closely, and does not mention 

 other equally important characters, such as the female claws. Another very valuable 

 paper is that published last year by J. R. Malloch on the American species."|" This, 

 however, has one serious fault, in that it ignores genital characters. The present 

 writer is largely indebted to both these papers for suggestions as to the classification 

 and description of the British species. For reasons which will be given later, however, 

 it has not been thought advisable to follow Malloch and Roubaud in subdividing 

 the genus Simulium. 



The writer is indebted to the following gentlemen for the loan of specimens (the 

 initials in brackets after the collectors' names are those used in the subsequent part 

 of this paper) : Messrs. E. A. Atmore (A.) ; A. E. J. Carter (Ct.) ; J. W. Carr (Cr.) ; 

 J. E. Collin (C.) ; P. H. Grimshaw (G.) ; A. H. Hamm (H.) ; F. Jenkinson (J.) ; 

 J. J. F. X. King (K.) ; C. G. Lamb (L.) ; C. Morley (M.) ; Lt.-Col. C. G. Nurse (N.). 

 In addition the following collectors, among others, have presented specimens to the 

 British Museum : Messrs. F. W. Edwards (E.) ; A. Piffard (P.) ; G. H. Verrall (V.) ; 

 Lt.-Col. J. W.Ye.rbury(Y.). 



General Morphology. 

 It is not the purpose of this paper to give a full account of the adult structure in 

 Simulium, but attention may be called to a few points which have either been in 

 dispute or have not been previously noted. 



* * Beitrage zur Kenntnis der Dipteren Finlands. vii Melusinidae (Simuliidae).' Acta 

 societatis pro Fauna et Flora Feniiica, xxxiv, no. 12, 1911. 



t U.S. Dept. of Agric, Bureau of Ent., Technical Ser. no. 26. 'American Black Flies 

 or Buffalo Gnats.' 



