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The Essex Naturalist
1993 Broom Hill (West Tilbury), Mill Wood Pit, Fobbing Hill and Linford
Sand Pit;
1994 Mill Wood Pit, Dagenham Chase, East Tilbury, Fobbing Hill and
Heybridge;
1995 Mill Wood Pit, Dolphin Quarry, Ferry Fields, Wanstead Flats,
Hatfield Forest (C Watson), Rushey Mead N.R. and Middlewick
Ranges (Bowdrey 1995).
Unknown Sphecidae
We are uncertain of the identity of the following species, records of which
appear in the literature.
Pemphredon unicolor Latreille
Listed for the Colchester area by Harwood (1884) without further detail. It is
unclear which species is inferred here. Psen unicolor (Van der Linden) is a local
species known from Dorset, Isle of Wight, South Hampshire, West Sussex,
South Essex, East Kent and West Kent. In the past, Psen unicolor covered a pair
of closely related species - Psen spooneri and Psen littoralis. The latter species is
most unlikely in Essex, being a wasp of coastal dunes in the west of England.
The true Psen unicolor was split off as recently as 1950. The only other aculeate
that includes the specific epithet unicolor in its synonymy is Tachysphex unicolor
(Panzer). We have been unable to locate any list containing the name unicolor
either attributed to Latreille or placed in the genus Pemphedron and so, for now,
the identity of this species remains unknown.
Crabro cephalotes Panzer.
Listed for the Colchester area by Harwood (1884) without further detail. It is
not clear if he is referring to Ectemnius (Clytochrysus) cavifrons sensu Saunders