l68 THE OAK GALLS AND GALL INSECTS
time included in the same genus. This similarity is much
greater between the sexual species of the genus Dryophania
themselves which cannot in some cases be separated at all, as
for instance, D. tachenbergi and D. similis which are practically
identical.
(25). Agamic Generation. I. Biorhiza aptera (Fab).
Gall.
Situated on the roots of the oak, either singly or in masses.
According to Adler they may also appear on the leaf stalk, but
those that he procured in this situation soon dried up. I have
myself never found the gall anywhere but on the root. Colony:
Pink to white when young, in some cases with a purplish tinge,
becoming brown with age. Soft at first, hard and woody
later.
Imago.
Colour: Yellow to reddish brown. Antennae: Darker towards apex.
Thorax: Parapsidal furrows distinct and usually complete, mesonotum especially
in the centre, slightly shining. Meso pleurae pilose. Scutellum and propluerae
finely punctured. Abdomen: Darker towards the apex. Legs: Yellowish
brown. Wings: None.
(25). Sexual Generation. Ia. Biorhiza terminalis (Fab).
Inquilines. Synergus facialis (Htg.) and S. melanopus (Htg).
Gall.
Grows chiefly on the terminal buds, but is frequently met
with on the lateral ones. Large, circular, and many celled, soft
and spongy at first, becoming hard and woody later. Colony:
Pink or bright red when young, turning brown with age.
Imago.
Colour: Yellow to yellowish red. Antennae: Darker towards the apex.
Thorax: Mesonotum shining and finely punctured. Pleurae shining and impunc-
tate Parapsidal furrows distinct. Scutellum wrinkled, with two basal foveae.
Abdomen: Brownish, on the dorsal surface darker in colour. Legs: Yellowish
red. Wings: Hyaline. Nervines brownish.
Account of Generation Cycle.
From the Biorhiza aptera galls the flies emerge in November,
December, and January (occasionally in March). They creep
up the trunk and lay their eggs very often high up in the tree.
The bud is first punctured with the ovipositor until riddled with
canals, into which the eggs are afterwards pushed, lying in a
mass at the base of the bud. The resulting Biorhiza terminalis