List of the Insect Fauna of the County. 131
Ulmaceae.
Ulmus campestris, Sm. Leaves. The galls mostly occur
at the ends of twigs on elm bushes or stubs ; they consist of
much thickened and distorted bunches of leaves, and vary in
size from that of a walnut to a fair-sized apple ; when fresh
they are yellowish green with rosy reflections, and contain a
quantity of bluish black mucilaginous liquid, which is
liberated with the Aphides when the mature gall splits. The
old brown galls are very conspicuous on elm hedges in winter,
but they are fitful in appearance, in some years (as 1881)
being very abundant, while in others (as 1879 and 1880)
they are almost entirely absent. Schizoneura lanuginosa,
Hartig.
Ulmus campestris, Sm. Leaf. These galls occur as
pedunculate, smooth galls, attached by their thin end to the
upper surface of the leaf, somewhat resembling a filbert in
size and shape ; they change colour, often to a beautiful
bright yellow, earlier than the unaffected leaves. They occur
singly, but I have rarely found double specimens ; unlike the
previous species these galls generally occur on trees ; they
are much rarer than S. lanuginosa, but in some years are by
no means uncommon. The gall-makers are mature in autumn.
Tetraneura Ulmi, De Geer.
Amentaceae.
Fagus sylvatica, L. Leaf. The gall is a hard, pyriform,
or somewhat conical, smooth projection from the upper side
of the leaf, but also showing through and firmly attached, so
that it falls only with the leaf; it is about the size of a
cherry-stone, and there are seldom more than one or two on
a leaf. The white larva pupates within the gall during
winter, Hormomyia Fagi, Hartig.
Fagus sylvatica, L. The small, hairy, tubular galls occur
on the upper side of the leaf, only showing a slight convex
projection on the under surface ; they are greenish at first,
but speedily change to brown or reddish brown in colour, and
then fall from the leaf, leaving a white, circular, basal scar