100 THE ESSEX NATURALIST
A number of beetles which are generally common throughout
Essex, have not been found on Skippers Island. Many of these
are 'obvious' insects, and would have been noticed if present in
any numbers. These 'notable absentees' include some of the
commonest ladybirds (Coccinella 7-punctata L., Adalia 10-
punctata (L.), etc.), many of the commonest ground-beetles
(Nebria brevicollis (F.), Trechus quadristriatus (Schrank), some
Agonum spp., Bembidion spp.), and the common species of
Cantharis, Meligethes, and other genera.
The channel separating Skippers Island from the mainland is
narrow, but together with the areas of salt-marsh on either side,
may form some sort of a barrier to those non-flying insects that
do not tolerate saline conditions. Particularly if the beetle fauna
of the island was reduced by the Great Flood of 1953, such isola-
tion may be a factor in limiting the number of non-coastal species
on the island.
If more extensive collecting can be done, to make the species-
list more complete, the 'notable-absentees' will be of greater
interest.
I am grateful to Mr. A. A. Allen for help with the Atheta spp.,
and to Mr. E. F. Williams for his kind invitations to visit Skippers
Island, and for his hospitality during these visits.
The nomenclature used is that of Kloet & Hincks (1945) except
where more recent work has shown this to be incorrect.
SPECIES LIST
Carabidae
Leistus ferrugineus (L.) (2), one specimen at grass roots, iii.60.
Dyschirius ludersi Wagn. (3), dry creek, ix.59.
Dyschirius salinus Schaum (2), shore refuse, iv.61.
Dyschirius globosus (Hbst.) (2) and (3), dry creeks, etc.
Bembidion varium (Ol.) (3), dry creeks, etc.
*Bembidion saxatile Gyll. (2), 1 ex. in shore refuse, iv.61.
Bembidion assimile Gyll. (3), beside the pond, 5 ex., iii.60.
Bembidion normannum Dej. (2) and (3), abundant in the dry
creeks and in shore refuse. Also from under dry seaweed
at the northern tip of Skippers Island.
Bembidion minimum (F.) (2) and (3), in the same situations as
B. normannum Dej., but less abundant.
Bembidion guttula (F.) (3), beside the pond, iii.60.
Bembidion iricolor Bedel (3), 20+ ex. from beside the pond,
iii.60.
Pogonus chalceus (Marsh.) (2) and (3), common in shore refuse,
and on the saltings.
Dicheirotrichus gustavii Crotch (2) and (3), shore refuse, and on
the saltings.
Amara antica (Panz.) (1), 2 ex. on ragwort flowers, ix.59.
Amara convexiuscula (Marsh.) (2), 1 ex. in shore refuse, ix.59.
Amara familiaris (Duft.) (2), 4 ex. in shore refuse, iv.61.