JOREA 
PREFACE 
Tue British Oak is the abode of a vast concourse 
of dependents. Nearly five hundred different species 
of insects, and other creatures, find their needs amply 
supplied, mainly by the leaves. Of this number 
about two hundred are either parasites living upon 
the larve of fifty-four species of Cynipide which 
produce galls, or they are inquilines obtaining their 
nourishment from the tissues of the galls. The Oak 
is therefore of great importance to insect life. 
The object of this volume is to describe and illus- 
trate, in some measure, galls produced by the Cynipidee 
and other causes of galls on the Oak. The insects, 
with their parasites. and other occupants of the galls, 
have been fully described by various writers ; several 
pages will, however, be devoted to a few interesting 
and unique features of the Cynipide. This volume is 
also the fulfilment of an intimation contained in the 
preface of my ‘British Vegetable Galls,’ explaining 
the reason why galls on the Oak were not described 
in that work. 
I trust the information herein contained may be the 
means of assisting many students to a further under- 
standing of the subject ; that collectors of these most 
interesting and dainty galls will be enabled to identify 
any specimen obtained; and, that casual observers 
will find in the illustrations and the text, such as will 
influence them to pursue the study in a practical 
manner. 
There is much more to be ascertained concerning 
