TWO NEW ESSEX GALL-MAKERS.
179
This year (1884), Mr. Inchbald has succeeded in rearing the
gall-gnats. On April 23rd, he wrote to me that he had bred two
males and one female. I was soon favoured with specimens, and,
under date May 3rd, I hear that "I have bred at least sixty, partly
males and partly females." Winnertz is the only other person who
appears to have bred the fly, and this, after repeated failures, in
1851, over thirty years ago. Mr. Inchbald gives the secret of
success :—"In rearing the gnat I find it absolutely necessary to
keep the soil in which the pupae are at rest well saturated with
moisture, thus imitating nature in her ways and means." His
notes on the insect are altogether so interesting that I transcribe
them :—
" The Cecidomyia cardaminis still continue to emerge (May 3rd, 1884). I
observe that the numbers that appear are considerable, especially if I deluge the
well rooted Cardimine plants with water over night; next morning gives me a
dozen or more of both sexes. They are very lively, especially the males, the
females are heavier in body and somewhat more sluggish than the males ; the
ovipositor which is much exserted is white and contrasts with the saffron-coloured
abdomen. I think I told you that the bitter cardamine (Cardamine amara) yielded
me even more galled heads than the meadow cardamine (C. pratensis); but not
one occurred on C. hirsuta. Both plants grow in the most spongy, treacherous,
boggy ground among Sphagnum moss—quite a black quagmire. Some of the
larger heads of crippled flowers are indeed monstrosities—the plant being hardly
recognisable except by its foliage—stamens and styles, calyx and corolla, capsules
and seeds are all made to assume monstrous proportions through the agency of the
larva of this gnat. I took up the plants—roots and all—from the Sphagnum
moss (a dozen plants in all) about the middle of May; the larvae were then nearly
fully fed. In a few days they crept forth from the flower heads and reddened the
surface of the soil, soon to disappear below. This was towards the close of May.
I gave an abundant supply of water, putting it into the saucer to be sucked up.
The water was periodically supplied, save in the winter ; as April came the
supply was increased and the gnats soon began to appear, four to six crawling up
the bell-glass every morning to dry their wings, which become fully developed in
about half an hour."
See also Mr. Inchbald's note in the "Field" for May 3rd, 1884
(vol. lxiii., p. 597). The tiny but beautiful rosy-red gnat with its
dark wings is well described by Francis Walker, after Winnertz, in
"Insecta Britanica, Diptera," vol. iii., page 83.
I may be permitted to repeat the appeal made some time ago
(Trans. E. F. C, vol. ii., p. 120) for aid in my endeavours to ascer-
tain the extent of our Essex gall fauna. I shall be pleased to name
any specimens that may be sent to me (at Maldon, Essex) direct,
or through the agency of our hon. secretary, and I am persuaded
that if a few members would take up the study, we might hope to
add very considerably to the list of the known galls of the county,
and even to detect species new to Britain.
K 2