INTRODUCTION. 



THE British entomologist desirous of obtaining' coloured illustra- 

 tions of his country's insect fauna finds that, as regards the 

 more popular Orders, such as the butterflies and moths, or the 

 beetles, ample provision has been made for his wants. Should his 

 predilections, however, incline towards Flies (Diptera), the case is 

 altogether different. For, with the exception of the excellent 

 coloured figures of certain British Diptera contained in Vol. VIII. of 

 Curtis's ' British Entomolog}'' (man\- of which were published more 

 than eighty years ago), and three plates of equally excellent coloured 

 figures included in Miss Staveley's ' British Insects ' (London : 

 L. Ree\-e and Co., 1871), no illustrations of British Flies in colour 

 are obtainable. It is hoped that the plates in the present work, 

 which faithfully depict the natural colours, and man}' of the external 

 structural characters of some of the most interesting and important 

 of Britisli Diptera, may do something towards meeting the deficienc}-. 



Although under the social conditions of modern life Blood- 

 Sucking Flies are less troublesome to human beings in the British 

 Islands than in some other less highly civilised countries, many of 

 the species illustrated in this book still often contrive to make their 

 presence inconvenienth- felt, while others in country districts are 

 regular tormentors of cattle and horses during the summer months. 

 Within the last few years Blood-Sucking Flies ha\e acquired a new- 

 importance, in view of modern discoveries as to the causation and 

 dissemination of certain diseases of man and animals, and although 

 no Blood-Sucking Fl)- is permanently associated with any disease in 

 the British Islands at the present da\', the British mosquitoes of the 

 genus Anopheles remind us of the time, still comparati\-ely recent, 

 when ague was rife in England, while Stovioxys calcitrans recalls the 

 Tsetse-flies of Tropical Africa, and the part played by them in 

 sleeping sickness and nagana. 



