190 THE YOUNG NATURALIST. [September 



The National Collection of British Diptera. 



By P. W. JARVIS. 



It is some twenty years since the late Mr. F. Walker named 

 and arranged the collection of British Diptera now located at the 

 South Kensington branch of the British Museum. During the 

 period which has elapsed since that time, many alterations and im- 

 provements have taken place in the nomenclature and classification 

 of the whole order, and it is high time that public attention should 

 be directed to the very unsatisfactory condition of this valuable col- 

 lection ; more especially as it not unfrequently happens that many 

 students visit the Museum for the express purpose of comparing 

 their specimens of this order with those in the Natural History 

 Collection. 



It appears that in Mr. Walker's time but little interest was mani- 

 fested in the above order, and that we possessed no one of sufficient 

 ability or discrimination to name the species which had from time to 

 time accrued to the nation. That the work which Mr. Walker en- 

 deavoured to accomplish was incomplete and inaccurate, has been 

 fully demonstrated by Prof. C. R. Osten Sacken, who made the fol- 

 lowing observations, respecting his efforts to enlighten the British 

 students thereon : — " Mr. Walker's writings on the order Diptera are 

 not better than his publications on Lepidoptera, Hemiptera, and 

 Orthoptera, as characterized by other authors. The same species 

 are often found described under several different specific names, and 

 placed in different genera ; well characterized species of a certain 

 genus are placed in the wrong, sometimes in very distant, genera, or 

 even in the wrong family. In the great majority of cases the de- 

 scriptions of new species were drawn from a single, often hardly 

 recognizable, specimen ; and when new species happen to be repre- 

 sented by more than one t}^pe specimen, these are almost sure to 

 belong to different species. Mr. Walker's identifications of the 

 species of former authors are often, I may say in most cases, in- 

 correct." 



That Mr. Walker's inaccuracies are not confined to his writings 

 on the subject, can be easily ascertained by any one who cares to 

 investigate the matter, by making a visit to the South Kensington 

 collection of the order Diptera. It is hardly necessary to give a 

 lengthy list of the errors which occur in this collection, and I will 

 limit my observations to two small and clearly defined families, viz. 



