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THE "ESSEX EMERALD" MOTH.
(PHOROSDESMA SMARAGDARIA, Fb.)
It is a matter of common observation with those interested in field
natural history that oftentimes species presumed to be rare, become
common in collections as soon as their precise localities and habits
are known. More particularly is this the case in entomology. Many
insects lead such retired lives, and have so many and unexpected
methods of concealment, that a collector ignorant of the habits
of the species he is in search of, may pass whole days in its special
locality, and perhaps meet with one or two chance specimens
only, the while a brother collector, more knowing in the ways of his
prey, will have filled his bottles or boxes in a few hours.
The pretty insect, Phorosdesma smaragdaria, was for many years
one of the rarest and most local moths in England, but since the
discovery of the habits of the larva, the species bids fair to be soon
represented by British examples in all good cabinets. The first
recorded native specimen appears to have been that beautifully figured
in Curtis's "British Entomology," vol. vii., pi. 300 (dated March,
1830), under the name of "Hipparchus smaragdarius." Mr. Curtis
remarked as follows :—
"For the loan of this rare insect, which is unique as British, I am indebted to
Mr. C. Parsons, of 'The Lawn,' Southchurch, Essex. Mr. Parsons found the
caterpillar in that neighbourhood, and the moth was hatched the 30th June, 1826."
Stephens, in his "Illustrations of British Entomology" (vol. iii.,
Haustellata, p. 180), alludes to Curtis's figure, and states that he had
never seen a specimen of the moth. Mr. Parson's specimen remained
the sole British representative of the species until 1845, when Mr. J. W.
Douglas and Mr. Haggar took five specimens "among grass on the
sea-wall" at St. Osyth ("Zoologist," 1845, p. 1089). Mr. Howard
Vaughan has kindly communicated to us the following extract from
the Diary of the well-known collector, the late Mr. Bouchard:—
"Jan. 20th, 1857.—A fine female smaragdaria, I think it ought to
be got earlier near Leigh." The exact locality is not stated, but Mr.
Vaughan suggests that it was Canvey Island, in the Thames estuary.
He adds, "I have heard that the late Mr. Ingall once accidentally
swept up a larva in Sheppey." In Stainton's "Manual" and in Noel
Humphrey's "Genera of British Moths," P. smaragdaria is stated
to have occurred at Southend, but no authority is given. Stainton