OF EPPING FOREST.
147
the largest of the group, is soft and spongey, and dries up with
age when the surface becomes wrinkled and irregular.
Imago.
Colour: Black. Antennae: Brownish black, furnished with long hairs;
thirteen jointed, twelfth joint as long as broad. Thorax: Scutellum, mesonotum
and part of the pleurae may be reddish brown. Abdomen: Black and shining.
Legs: Black. Femora and upper parts of tibiae, reddish brown. Wings;
Hyaline, long; cubitus, and radial cellule at base, dark.
(7). Sexual Generation. Ia. Dryophanta taschenbergi
(Schltdl).
Gall.
Length 2-3 mm. Appears usually from the adventitious
buds on the trunk of the tree or from buds on young shoots
which have grown from these adventitious buds. Shape: Oval,
apex rounded. Purple in colour and velvety in appearance;
there is an inner gall which is soft and starchy.
Imago.
Colour: Black, shining. Antennae: Black. Thorax: Black, smooth and
shining; scutellum dull. Abdomen: Black. Legs: Yellowish, trochanters
black, femora infuscated. Wings; Hyaline, long and smoky.
Account of Generation Cycle.
Although the perfect insect begins to gnaw its way out of the
Dryophanta folti gall in November, it does not usually emerge
until the following March, the exact time of its appearance
varying according to the temperature.
The eggs are then laid in the adventitious buds on the trunk
of the oak tree, one egg in each bud at the base of the bud axis
(sometimes also in the buds of twigs). The resulting gall
D. taschenbergi, appears at the end of April and during May,
maturing at the end of the latter month. The flies emerge from
these galls at about the beginning of June, the females ovipositing
in the veins of the softer leaves always at the back of the leaf.
Dryophanta folii galls appear early in July and mature in
October, usually falling to the ground when this stage is reached.
OCCURRENCE IN EPPING FOREST.
Dryophanta folii. Very abundant. When young the gall is
covered with minute nodules lighter in colour than the rest of
the gall, which subsequently disappear when the gall reaches
maturity. In some instances I have found as many as five of
these galls on one leaf, completely weighing it down. First
appearance noted, July 19th.