ON BRITISH OAKS. Ti 
value. Care should be taken to leave all seedlings which may 
have sprung up, but none of the shoots from the stools should be 
left, however promising they may look, as trees grown from such 
are generally faulty at the butt, and otherwise unsatisfactory 
when they attain maturity. The trees being now about thirty 
years of age, some of the short stemmed ones will come in as 
useful timber, but no more should be taken out than is absolutely 
necessary to make room for the others, as no greater mistake can 
be made than in taking too many trees at a time. 
DISEASES OF THE OAK. 
Insects. 
The oak, although lord of the woods, is more subject to the 
attacks of insects than any other tree of the forest. One authority 
has stated that there are nearly 130 species of galls living on 
various kinds of oaks in Europe. In this paper it will be 
sufficient to notice only those that are common in Britain. 
First, the Marble Gall, so called from its appearance, being 
like a common marble as used by boys in play. It is perfectly 
round, brown, and gets very hard in autumn, and with clusters of 
three or four gives the tree a strange appearance when denuded of 
leaves. It occurs mostly on young trees, or those that have been 
pollarded, seldom or never on large growing trees. This gall is 
produced by an insect known as Cynips Kéllarz. Its history is 
somewhat obscure ; but the grub occupies the centre of the gall, 
and lies in a curved position, emerging from it In spring a perfect 
fly. During the winter many of the galls are pierced by birds 
and the grub extracted. This, no doubt, tends to check their 
increase. 
The Apple Gall, or ‘oak apple,” is occasionally very plentiful, 
and generally found at the end of a shoot. The galls begin 
to form at the end of April or beginning of May, and are full 
grown by “oak apple day,” or the 29th of May, the anniversary 
of the restoration of Charles II. Sometimes they are 1} inches 
in diameter, of a greenish-white colour streaked with red, at first 
soft, but harden somewhat before they fall from the tree ; they 
are then found when opened to contain many grubs, each in a 
separate cell, The perfect insect, Terax terminalis, emerges in July. 
The Root Gall—The females deposit their eggs in the roots 
