In the following pages no attempt has been made to supply a 
detailed technical description of each species illustrated in the plates. 
In the case of the majority of the species, at any rate, it is believed 
that the plates will render such descriptions unnecessary, and, apart 
from this, the many demands upon the author's official time would 
have made their preparation impossible. The same reason, coupled 
with limitations of space, has also unfortunately necessitated the 
omission of a considerable amount of matter relating to the life- 
history of the species mentioned, but brief notes on life-history are 
included in the remarks upon each family. Since it was thought 
that British readers might be interested to learn in what other 
countries our native Blood-Sucking Flies are found, the geographical 
distribution of each species so far as it is known has in all cases been 
stated. References to original descriptions of genera and species, 
and discussions of synonymy, though necessarily included in a 
monograph, have here been omitted as out of place in a work which 
does not profess to be more than a popular account of the insects 
of which it treats. Since the primary object of this book is to 
facilitate by means of the plates the identification of Blood-Sucking 
Flies, the males that (probably with the exception of those of species 
belonging to the Muscidae and Hippoboscida?) do not suck blood 
have not, as a rule, been illustrated. 
The original water-colour drawings of the species represented 
have been prepared by Mr. A. J. Engel Terzi with his usual care and 
exceptional skill, and a word of acknowledgment is also due to 
Mr. Harry F. Witherby (of Messrs. Witherby and Co.), who has 
personally supervised their reproduction, and has been unremitting 
in his endeavours to produce thoroughly satisfactory copies of the 
artist's beautiful work. A special feature deserving of note in 
connection with the illustrations is the use of permanent paper for 
the plates, instead of the perishable coated paper generally employed 
for three-colour work. The change has greatly increased the 
difficulties of reproduction, but it is hoped that it will be appreciated 
by purchasers of the book. 
Field notes on many of the species illustrated and mentioned in 
the text have been kindly contributed by Lieut-Colonel J. W, 
