List of the Insect Fauna of the County. 101
folk-lore of galls would yield a goodly chapter, but with
little help towards the present enquiry.7 Compare the well-
known remarks of many classical writers, and some curious
information given in Kirby and Spence's 'Introduction to
Entomology.'
Linne tells us the insect punctures the plant, and the out-
flow of sap from the wound is the cause of the formation of
the gall. "Cynipes succo plantarum e vulnere inflicto
stillante et in gallam in qua habitant larvae excrescente
victitant." [Gmelin's Linne, 'Syst. Nat.,' vol. i., pars. v.,
p. 2650.]. De Geer, Reaumur, Roesel, Frisch, Malpighi, and
others had previously promulgated this convenient but
thoroughly untenable theory; still this was generally
accepted to the days of our own Kirby and Spence.
These fathers of British Entomology epitomized the in-
formation on this puzzling subject thus :8—" How the mere
insertion of an egg into the substance of a leaf or twig, even
if accompanied, as some imagine, by a peculiar fluid, should
cause the growth of such singular protuberances around it,
philosophers are as little able to explain as why the insertion
of a particle of variolous matter into a child's arm should
cover it with pustules of small-pox. In both cases the effects
seem to proceed from some action of the foreign substance
upon the secreting vessels of the animal or vegetable ; but of
the nature of this action we know nothing. This much is
ascertained by the observations of Reaumur and Malpighi—
that the production of the gall, which, however large, attains
its full size in a day or two, is caused by the egg or some
accompanying fluid,—not by the larva, which does not appear
until the gall is fully formed; that the galls which spring
from leaves almost constantly take their origin from nerves ;
and that the egg, at the same time that it causes the growth
of the gall, itself derives nourishment from the substance
7 References to fossil galls and some antiquated information occur in
Mr. Albert Muller's memoir, 'In Memoriam Wilson Armistead, of Vir-
ginia House, Leeds.' 'Zoologist,' 2nd ser., vol. iii., pp. 1196—1208;
May, 1868.
8 'An Introduction to Entomology.' By William Kirby and William
Spence. 4th ed. (1822), vol. i., p. 450; 5th ed. (1828), vol. i., p. 448.