100 BRITISH OAK GALLS. 
seen that the larval chamber of this species is very 
much larger than that of A. radicis. 
The galls of B. aptera may readily be obtained by 
removing earth with a small trowel, or a piece of stick, 
from the side of a bank on which an oak tree is grow- 
ing. A position similar to that depicted on Plate 
XXXII, will yield an abundance of specimens. They 
are always covered with earth—sometimes sparingly— 
and usually at a depth of about three inches. 
In the year 1873 some of these galls were found on 
the roots of Deodars at Wimbledon, and were exhibited 
at a meeting of the Royal Horticultural Society by Dr. 
Masters. It was considered to be the first instance in 
which a Cynips had been known to attack any species 
of Conifer. They have since been found on the roots 
of Prunus, Fagus sylvatica, and Vitis vinifera. 
The male imagines are always alate, the females are 
mostly apterous; occasionally there are rudimentary 
wings. Upon leaving the gall the female creeps up 
the bole of the tree, along a limb, and after choosing a 
terminal bud, bores a large number of holes with her 
ovipositor ; the ova being afterwards pushed down the 
holes until they form a mass at the base of the bud. 
The operation of oviposition is sometimes very pro- 
tracted. Dr Adler observed that one female occupied 
eighty-seven hours in depositing 582 ova in two buds 
(‘ Alternating Generations,’ p. 72). 
The presence of so large a number of ova (about 290), 
and a corresponding number of holes, in so small a 
bud as that of the oak, must inevitably injure the 
interior, and extensive destruction of the tissues of the 
plant does actually take place ; so much so that occa- 
sionally the whole bud axis is cut through, and no gall 
formation takes place. When, however, gall formation 
begins the apex of the real bud is severed from its 
twig, and, remaining loosely attached to the swelling, 
is lifted up and retained for some time. See Plate 
LVII, div. A. 
The beautiful photo-micrographs on Plate XXXII, 
