178 TWO NEW ESSEX GALL-MAKERS.
altered leaves. The specimen sent to me by Mr. Christy is pure
white in colour, but the galls are generally tinted with pink. Mr.
Peter Inchbald, F.L.S., first bred the insect in Britain in 1860, and
thus records his observations, under date August 17th, in the
"Entomologists' Weekly Intelligencer," vol. viii. (1860), p. 164:—
" I have recently succeeded in hatching the Cecidomyia that forms a nidus for
its offspring on one of the milfoils (Achillea ptarmica), and unlike many of the
race, it emerges from its pupahood in the autumn. The galls produced by the
parent fly are far from unsightly. It would seem to pierce the summits of the
plant, which in consequence becomes stunted, and instead of producing their
tufts of flowers, transform themselves into woolly galls of a pinkish colour. I am
unable to ascertain, from the scanty specific characters given by Meigen, to which
of the Cecidomyiae I am to refer the insect in question. It has the aspect of
Cecidomyia producla. It is a pretty little fly, with the abdomen reddish brown
and the wings velvety and longitudinally nerved, as is the case with all these gall-
flies. The ovipositor is telescopically formed, and consequently much exserted."
The Hormomyia ptarmica was accidentally omitted from my list of
the galls of Essex, as I find that I gathered the gall at Rayleigh, either
in 1873 or 1874. It should immediately precede the Yarrow gall
(Hormomyia millefolii) in my paper "The Galls of Essex" ("Trans.
Essex Field Club," vol. ii., p. 127, fig. 11), which occurs commonly
on Achillea millefolium, but which is also found on Achillea
clavennae (F. Low, Verb. z.-b. Gesell. Wien., xxvii., 32), A. ptarmica
(J. W. H. Trail, Trans. Nat. Hist. Soc, Aberdeen, 1878, p. 65),
and A. nobilis (F. Low, Verh. z.-b. Gesell. Wien., xxxv., 499). The
figure of H. ptarmica given above, is from a drawing by Mr. H. A.
Cole, taken from Mr. Christy's specimen.
II. — Cecidomyia Cardaminis, Winnertz, on Bitter - Cress
(Cardamine.)
[Read May 24th, 1884.]
On June 12th, 1882, Mr. Peter Inchbald, F.L.S., sent me specimens
of the galls of this gnat from Harrogate—my first acquaintance with
them; on June 13th, 1883, Mr. W. C. Boyd sent me the galls (on
Cardamine pratensis) from Fay Gate Station, near Horsham, Sussex,
and the next day I found a few galled flower-heads of this plant (C
pratensis) at Maldon in Essex. On June 15th, Mr. Inchbald again
supplied me with the galls, on Cardamine pratensis and C. amara.
Doubtless this little insect with its interesting gall occurs in other
Essex localities, and it should be well looked for when the Carda-
mine is in flower. Cecidomyia cardaminis bears the same relation to
the plant that bears our bonnie cuckoo-flowers that Cec. sisymbrii
does to the water-cress, etc., and the two galls may be found together.