34 THE ESSEX NATURALIST
bud or at the rough ring at the base of the year's growth. I
believe they are deposited all over the tree, for on one occasion
whilst visiting a wood in autumn, where many of the oak trees
had been felled, I examined the top twigs and found eggs on
many of them. The egg is shaped like a sea urchin, being about
0.4mm. high and 0.8mm. in diameter; it has a raised network
of hexagonal cells on the surface, much finer near the micropyle.
When first deposited in August it is a dull white but becomes
darker with age and does not hatch until April. (Fig. 4.)
The Silver-spotted Skipper (Hesperia comma). The eggs of
this species are placed singly on grasses; they are attached by
the base, which is about 1mm. in diameter, the height being
0.7mm. The shape may be likened to an inverted pudding
basin. When laid they are a pearly white but change to a chalky
white before hatching, and the surface is covered with minute
pits. Deposited in August, they do not hatch until March.
(Fig. 5.)
The Brimstone (Gonopteryx rhamni). The eggs, which are
shaped like a champagne bottle, are placed on the underside
of a young leaf of buckthorn. They are 1.3mm. high and
0.5mm. in diameter. There are some 11 longitudinal ribs and,
between them, a number of cross-bars. Green at first and
changing to a yellow colour, eggs may be found from May until
July, and hatch in about 10 days. (Fig. 6.)
OAK GALLS IN EPPING FOREST
BY JOSEPH ROSS
FOR some years I have been searching oak trees (Quercus
robur L.) in Epping Forest at the time they bear male
catkins, in the hope of finding inhabited galls of Andricus
solitarius Fonscolombe form occultus Tschek. Before the war
I found a few of these galls in the Lower Forest beyond Epping,
but when found the flies had already left them. On 30th April,
1944, I captured two female flies of this form on Pear Tree Plain,
on an oak tree.
During the afternoon of 22nd April, 1946, I noticed the broken
bough of an oak lying in that part of the Forest near King's
Head Hill, Chingford, known as Hawk's Mouth, and proceeded
to look over it. The bough, which had been growing out of
reach of anyone standing on the ground, bore many male catkins,
with galls of the form occultus; those most readily seen showed