148 THE OAK GALLS AND GALL INSECTS
Dryophania taschenbergi. Very plentiful, especially growing
from adventitious buds on the trunks of old trees. I have also
found some of the galls on the buds of twigs, growing quite at the
base of the trunk. When old, these galls lose their velvety purple
appearance and assume a dull brown colour, often remaining on
the trees for a considerable time after the insects have emerged.
First appearance noted, May 18th.
(8). Agamic Generation. II. Dryophanta longiventris.
(Htg.) Inquilines. Synergus pallicornis (Htg.) and S. apicalis
(Htg.)
Gall.
Found on the under-surface of the leaf arising from the leaf
veins. Shape: Globular, the surface often being nodulated and
sometimes winkled. Colour: Green to yellowish white, often
marked with reddish stripes.
This gall is hard and woody, the central cavity is small and
the walls are thick. The top is not depressed. It is much
smaller and more flattened than D. folii.
Imago.
Very similar to Drophanta folti, the only tangible difference being in the
antennae, which have the 12th joint less broad than long. There are no other
constant characters by which these two insects can be differentiated.
(8.) Sexual Generation. IIa. Dryophanta similis.
(Adler).
Gall.
Very similar to D, taschenbergi, but more slender and
pointed. It is covered with hairs, which are longer and whiter
than is the case with the D. tachenbergi gall, which give
the original green colour a somewhat greyish appearance. I have
found these galls slightly purple in colour.
Imago.
Almost identical with D. taschenbergi, though generally somewhat
darker in colour.
Account of Generation Cycle.
The Dryophania longiventris gall is very liable to parasitic
infestation. The perfect insects mature in November and
December, when they sometimes emerge, but usually they do not
appear until March. The date at which they leave the gall
depends a great deal upon the temperature. They lay their