PREFACE, 
Tue present work by Prof. Mario Bezzi, which gives an 
account of the African Diptera of the family Syrphidee, and 
which greatly advances our knowledge of those insects, has 
only been made possible by the richness and completeness 
of the collections submitted to him for examination, by the 
Imperial Bureau of Entomology. These collections are now 
in the British Museum (Natural History), to which they 
have been presented by the Imperial Bureau, and have added 
very considerably to the importance and value of the 
collection of Syrphidze already there. 
The thanks of the Trustees are due to Mr. Guy A. Kk. 
Marshall, Director of the Imperial Bureau, for the care with 
which he had revised the greater part of the MS. for the 
press. Mr. E. E. Austen and Mr. F. W. Edwards have also 
rendered assistance in correcting proofs and in other ways in 
which their special knowledge of the Diptera has been of 
great advantage. 
CHARLES J. GAHAN. 
British Mustum (Natura Hisrory), 
March 1915, 
