OF EPPING FOREST.
153
Andricus testaceipes. Not plentiful. I found galls both on the
petiole and mid-rib of the leaf.
First appearance noted, June 15th.
(12.) Agamic Generation. II. Andricus corticis (Linn.)
Inquiline. Synergus incrassatus (Htg.).
Gall.
Found on the oak trees in places where the bark has been
injured, as when a branch has been sawn off or broken by
wind. The gall is covered over in a thin sappy yellowish
rind, which afterwards falls off and leaves the gall exposed. The
larval chamber is sunk deep in the wood, the upper half, which
projects, being shed at maturity. The punctured rims then
plainly mark the presence of the galls.
Imago.
Colour: Brownish black. Antennas: Dark brown, base reddish. Thorax:
May be slightly hairy, dark brown and smooth. Abdomen: Lighter in colour
than the thorax. Legs: Reddish brown.
(12.) Sexual Generation. IIa. Andricus gemmatus
(Adler).
Gall.
Small, only 2 mm. in length. Appears in the leaf axil or
growing from axillary buds. The apex of the gall only may
appear. I have found this gall on the leaf as well as in the bud,
when the shape is oval, the rind smooth and thin, and the apex
may be narrower. Green to brown in colour, though I have
sometimes found it quite red. Often it is very similar in appear-
ance to N. albipes. I have also found it attached to the
petiole of the leaf.
Imago.
Colour: Black, shining. Antennae: Brownish black, base paler. Thorax:
Dull black. Abdomen: Dark, with brownish red ventral surface. Legs:
Yellowish red. Base of femora dark, but much lighter in colour in the male.
Account of Generation Cycle.
The flies emerge from the A. corticis galls in April and May,
and lay their eggs deep in the bud. The resulting gall, A.
gemmatus, appears in June, and the insects emerge in July or
August. I have never seen the insects of the sexual generation
engaged in ovipositing. This takes place in injured parts of the