OF EPPING FOREST. 161
begin to form in July, at the beginning of the month. These are
A. fecundatrix galls, and they do not as a rule give up the
perfect insects until April of the second or third year. In
August of the first year, and before it is mature, the inner gall is
often thrust out by the scales and falls to the ground.
OCCURRENCE IN EPPING FOREST,
Andricus fecundatrix. Fairly abundant. In some instances
twigs of some length may have galls appearing from every bud.
I have often found the inner galls to be parasitised and
polythalamous. The scales which form a covering for the inner
gall may remain upon the tree for a considerable period; they
often continue on the tree during the following summer. First
appearance noted, July 12th.
I was unable to find any A. pilosus galls in Epping Forest.
(18.) Agamic Generation. VIII. Andricus malpighii
(Adler).
Gall.
Very like A. callidoma, and found also in the axils of the
leaves. It can be told, however, by the absence of the long
thin stalk, which gives the gall a plumper appearance, the stalk,
if present, being very short and thick. Parasitised A. callidoma
galls often resemble A. malpighii, but as the latter appear at a
much later date they can usually be distinguished.
Imago.
Can scarcely be told from A. callidoma, but it is usually darker in colour; the
femora and upper half of the tibiae are dark.
(18.) Sexual Generation. VIIIa. Andricus nudus.
(Adler).
Gall.
Found on the male catkins between the anthers. Glabrous,
but with sometimes a few hairs at the apex. Colony: Green
when young, becoming yellow at maturity. Shape: Elongated
oval.
Imago.
Colour: Black. Antennae: Dark, basal 4-5 joints yellow. Thorax: Slightly
shining. Abdomen: Paler than the thorax, ventral surface usually testaceous.
Legs: Yellow, the base of the anterior coxae may be dark.
Account of the Generation Cycle.
The flies from the A. malpighii galls emerge in April and
oviposit in the male catkin. A. nudus galls are formed in May,