204
THE ESSEX FIELD CLUB.
Mr. Henry Walker exhibited one of a series of photographs of lightning
flashes, taken in Bayswater during the great storm of August 17th last, by
Mr. E. Sanger Shepherd. Mr. Walker remarked that it showed in a notably
superior degree the characters of all similar photographs he had yet seen. As
far as was known at the Meteorological Office, the number of such photographs
existing in Europe and America was about fifty, and they all agreed in show-
ing that there was really no such thing as zig-zag lightning. All the photographs
exhibited the course of the flash as a gently meandering line, like a river on a
map, with a few ramifications of a fainter character. While the storm lasted,
Mr. Shepherd exposed fifteen plates, and seven of the photographs were
successful. The apparatus was a half-plate, square box camera, fitted with a
portrait lens. In the discussion which ensued, in which Messrs. Thorp, White,
Tilding, Royle and others took part, several explanations were put forward
as to the origin of the popular pictorial lightning flash, and Mr. Walker spoke
of the precautions necessary in taking such photographs as that exhibited.
Late Stay of Swifts.—Whilst shooting in the parish of Ramsey, near Har-
wich, on September 16th, I noticed a pair of swifts. Is not this very late for
these birds?—C. H. Norman, Mistley Place, Manningtree.—Swifts stayed
here 'late this year. On September 19th, I watched a pair hawking about
tamely over the beach at Stone Point, near Walton-on-the-Naze.—Lieutenant
Colonel Marsden, Colchester. [These records are from "Field" of October
1st. Several further notes have appeared in the issues for October 8th and
15th, referring to the late stay of swifts. J. D. Moffatt records them from
Sefton Park, near Liverpool, on October 5th; F. Brown from near Croydon,
on October 9th ; and E. T. Booth from Brighton, to October nth. As a rule,
the swift is seldom seen here after the first week in September, and in many
parts of the country it departs in August. The bird probably works it way
gradually towards the coast, so that the southern and south-eastern counties
would be the latest visited.—E. A. F.]
Phorodesma smaragdaria, F. (The "Essex Emerald Moth").—In the
interesting account of this Essex moth in the Essex Naturalist, page 120, line 4
from bottom of page, we read" He adds, 'I have heard that the late Mr. Ingall
once accidentally swept up a larva in Sheppey.' "This record, I think, refers to
an Essex specimen, as stated in Newman's "British Moths" (page 70):—"My late
friend, Thomas Ingall, found the caterpillar of this species on the Essex coast,
but did not know what a prize he had obtained until the moth emerged." Mr. J.
W. Douglas gave a translation of G. Koch's life-history of this species (Stett. Ent.
Zeit. xii., 265-7) in the "Proceedings of the Entomological Society of London ''
for March 1st, 1852 (page 5). Achillea millefolium is there given as the food
plant. In addition to the Yarrow and the Artemisia it has been bred from the
Salad Burnet (Poterium sanguisorba), Tansy ( Tanacetum vulgare) and Wood
Senecio (Senecio sylvatica) by Muhlig, Blum, Kindermann, and Rossler. P.
Milliere, who found the species in the Lyonnais in 1845, but not again till 1872,
describes and figures the larva in and out of its case ana the imago in his beauti-
ful work ("Iconographie et Description de Chenilles et Lepidopteres Inedits,"
vol. iii., page 423, plate 152, figs. 16-18 ; 1874). The larva was received from
Dr. Staudinger. Of it he says, "On dit que cette chenille vit sur les arbres.
J'en douterais, en egard a la nature des materiaeux employes a la formation de son
fourreau portatif. Au reste M. Freyer la represente sur le millefeuille [yarrow] ;
ce que confirme M. 1'abbe Fettig qui l'a elevee." The larva is badly figured on
Yarrow in Kirby's "European Butterflies and Moths," plate 47, fig. 4. This
species is now known to occur on our Essex coast from Fobbing and Corringham
Marshes to St. Osyth; probably wherever Artemisia maritima occurs, in "Dis-
tricts" 5, 6, 7, and 8 of Gibson's "Flora," and it may also affect the other food
plants mentioned.—Edward A. Fitch, Maldon, September, 1887.