282 OAK GALLS AND GALL INSECTS
It is exceeding difficult to differentiate between the species
of this genus, as the different individuals vary to such an extent
among themselves that it is almost impossible to separate them
in many cases, the specific characters rarely remaining constant.
For this reason I have not here described the different species,
but an excellent account of this genus has been given by Mr.
Cameron.3
With regard to the galls to be hereafter described, the
inquilines inhabiting them are also given in each case.
Two other genera include insects found as inquilines in oak
galls, namely, Ceroptres (Hartig) and Sapkolytus (Foerster). In
the former, one species, Ceroptres arator, is mentioned by Cameron
as present in galls of Andricus noduli from Clydesdale, and it is
also said to have been reared from Cynips kollari galls. The
genus Sapkolytus contains only one British species, S. connatus
(Htg.) also bred from Andricus noduli galls. The characters of
these two genera have been given by Mr. Cameron in his work
already referred to.
It very often happens that after taking great trouble to
breed Cynipidae from a number of different galls one only
succeeds in rearing a large proportion of inquilines and parasites.
This is very naturally the cause of much disappointment,
especially when one is just commencing to collect. Synergidae
are very easily mistaken for the gall makers, which they greatly
resemble, though as a rule one soon finds plenty of opportunity
for ascertaining their exact appearance. True parasites are
easily distinguished.
Collecting Galls.
To any one commencing a study of Oak galls who requires
to obtain specimens for a collection or for breeding purposes, a
great deal of time might be saved, in the case of some species, by
first looking through a collection such as that at South
Kensington and thus obtaining some of the idea of the exact
appearance of the galls before going out to search for them.4
There are many species which are by no means easy to find even
when you arc aware of their exact appearance ; such galls as
3 Peter Cameron's Monograph of British Phytophagous Hymenoptera, vol. iv. London
Ray Society, 1882-92.
4 It is anticipated that by th i Spring of 1903 a typical collection of galls and gall-insects,
with drawings and other illustrations, will be placed in the Club's Epping Forest Museum in
Queen Elizabeth's Lodge, Chingford, Essex.—Ed.