OAK GALLS AND GALL INSECTS.
139
the galls were figured in Mr. Fitch's paper, in the second volume
of our Transactions,3 and that coloured figures are given in
Dr. Adler's and Mr. Cameron's books, to which attention has
been directed.—Ed.
ORDER HYMENOPTERA.
Family CYNIPIDAE.
Sub-Family CYNIPINA.
Genus NEUROTERUS (Htg.).
This genus contains, besides several from America, eleven
European species. In the sexual form the perfect insect has the
ovipositor short and nearly straight, the eggs being laid in the
leaf; the agamic forms have the ovipositor longer and more
spiral, as the eggs in this case are laid in the buds. The agamic
form also has the abdomen larger, but more compressed than in
the sexual form. Neuroterus punctatus and Neuroterus politus are
the only two British species already known that do not make
galls; the former has been taken from oak buds, but without
distorting them in any way. The agamic forms all make flat
spangle galls on the backs of oak leaves, with the exception of
N. aprilinus; the galls of the sexual generation differ in position
and appearance, the eggs being always laid in the bud and not
on the leaf.
General colour black. There is no suture between the
mesonotum and the scutellum.
Sexual forms have the legs light yellow.
Agamic forms have the legs darker.
(1.) Agamic Generation I. Neuroterus lenticularis (Ol.)
Inquiline. Synergus tscheki (Mayr.)
Gall.
Appears on the under surface of the oak leaf (diameter 4-6
mm.) Colour: Yellowish-red. Under-surface flat, white and
glabrous. Shape: Rounded, conical in the centre. Numerous
on the leaf.
Imago.
Colour: Black. Antenna: Brownish, 15-jointed, 2-3 basal joints yellow.
Thorax: Rough and finely punctured. Mesonotum: Shagreened. Abdomen:
Compressed and shining. Ovipositor: Curved and longer than the abdomen.
Legs: Yellowish; bases of femora and coxae darker. Wings: Hyaline;
first cubital cellule slightly clouded.
3 "The Galls of Essex," Trans. E.F.C. II. pp. 98-156.