INTRODUCTION. 



THE principal object of the present Catalogue has been to give 

 a complete list of the specimens of Hymenopterous Insects contained 

 in the collection of the British Museum, indicating at the same time 

 the peculiarities of each, as regards variations in colour, locality, 

 and the source from whence it has been derived. 



With this view, the different individuals of each species contained 

 in the collection are indicated by the letters , b, c, c., following 

 the name of the species, and its synonymes. 



In the adoption of generic and specific names, it has been thought 

 right to use, wherever it was possible, that which was first applied 

 to the species. As far as regards the specific names, there is com- 

 paratively little difficulty in the application of this simple rule ; but 

 generic names have been used by different authors in senses so 

 widely different, and the groups which they were meant to designate 

 have been so variously extended or restricted, that it is no easy 

 matter to determine, where several names have been used, which of 

 them ought to be preferred. 



