y 



^ {W 





INTRODUCTION. 



The principal object of the present Catalogue has been 

 to give a complete list of the specimens of Dipterous Insects 

 contained in the collection of the British Museum, indicat- 

 ing at the same time the peculiarities of each, as regards 

 I variations of character, locality, and the source from whence 

 l it has been derived. With this view, the different individuals 

 of each species contained in the collection are indicated by 

 the letters a, b, c, &c, following the name of the species and 

 its synonymes, and the description, if it appeared to have 

 1 been before undescribed. 



This part of the Catalogue of Dipterous Insects has been 

 | prepared and the new species described, by Mr. Fbangis 

 | Walker, so well known for his attention to this order of 

 Insects. 



The remaining part, containing the other families, is in hand, 

 and will follow as soon as it can be completed. 



JOHN EDWARD GRAY. 



British Museum, 



June 6th, 1849. 



if 1* 

 i 



