2
AN APPEAL FOR RECORDS OF THE SPIDER Nigma walckenaeri
Last year I made an appeal for records and specimens of the spider Nigma walckenaeri
and this resulted in a new 10Km square record for the species at Purfleet from our
member John Davidson. Nigma is small green spider makes its web across the upperside
of leaves with a concave surface and then sits underneath between the leaf and the web.
Plants such as Lilac, Forsythia and Holly are favoured.
The spider is nationally notable, apparently confined to the London region, particularly in
gardens and parks, but in recent years it has been found as far afield as Southend and
Colchester. The spider may well occur elsewhere in Essex and I would urge members to
look in their garden and local neighbourhood for the spider. It is now in evidence, and
will be maturing soon, lasting into the early autumn.
I would be grateful for a sample specimen of any that you find, with details of the
location and date, preferably also with a grid reference. An old film container or similar is
excellent for safe custody of the spider, together with a leaf to maintain some humidity. I
will gladly refund postage and let you know if the spider is indeed Nigma walckenaeri..
Peter Harvey, 9 Kent Road, Grays, Essex, RM17 6DE
A NEW WOODLOUSE IN ESSEX
Mr Jon Daws reports in the latest Newsletter of the British Isopod Study Group the
finding of Eluma purpurascens at Canvey Island in Essex. He visited the area in
November 1992 to look for the species Halophiloscia couchi at a locality mentioned by
Collinge, but with no success turned to a landfill site that had been capped three years
previously for a change of habitat. A small part of the site was still being used as a
collection site for refuse, with the rubbish being removed in skips. A search behind the
furthest skip where there was an overgrown ditch and plenty of rubbish to rummage
through produced a total of three specimens of Eluma purpurascens, together with the
species Porcellionides pruinosus under rotten logs on a nearby embankment and
elsewhere around the site.
Eluma is a pill-woodlouse, but can easily be distinguished from the common
Armadillidium vulgare by each eye consisting of a single large ocellus. In England the
species was reported from only two sites, one in east Norfolk and the other near Herne
Bay, Kent, but in the last few years it has been found in about a dozen further locations in
Kent (Hopkin, 1991). It occurs on coastal cliffs and inland synanthropic sites.
Woodlice are yet another under worked invertebrate group in Essex, and the fully
illustrated AIDGAP key by Dr Stephen Hopkin to the 35 species of woodlice known to be
native or naturalised in Britain and Ireland is very much to be recommended (Field
Studies Vol. 7 No. 4 (1991).