but it is a scarce and local species which was much commoner in the
past, especially in southern heathland districts (Falk, 1991). I found
one female walking up the side of the concrete sea wall at East Tilbury
(TQ6977) in August 1992. The Small Velvet ant Smicromyrme rufipes
(Fabricius) (Notable B), a cleptoparasite of a wide variety of ground-
nesting bees and wasps appears much commoner in south Essex with
recent records from a number of sites, mainly old sand pits where the
wingless females can be found running over bare sand in the vicinity of
aculeate burrows.
Family Eumenidae
Several specimens of Odynerus melanocephalus (Gmelin) (Notable A)
were taken at Chadwell in June 1993. The species is widely recorded
in southern England but its modern strongholds are the coasts of the
Isle of Wight, Dorset and Kent. Records from further areas are sparse
and suggest a substantial decline (Falk, 1991).
The small black solitary wasp Crossocerus distinguendus (Morawitz)
(Notable A) was first found in the county in 1989 by Mark Hanson in
Epping Forest at Yardley Hill. During 1993 two more specimens (conf.
J. Felton) have turned up in Essex. I collected one male on the 28th
May in my garden in Grays (TQ6277) and a second male on the 1st July
in the Flitch Way Country Park (TL6121), a stretch of disused railway
track west of Great Dunmow. Yet another male was amongst some
material that I looked at recently, collected in September 1988 by Colin
Plant in his garden in Bishops Stortford (TL4820), just over the border in
Hertfordshire.
The species is apparently increasing in frequency and largely associated
with unthreatened, often artificial habitat types. Nesting usually occurs
in sand or gravel slopes or vertical banks fully exposed to the sun. It
has even been discovered nesting in a rockery at a railway station (Falk,
1991). The wasp has been taken on a number of occasions in gardens,
as in two instances reported here. The species is very similar to the
common Crossocerus elongatulus (Van der Linden), but the absence of
records in Britain before the 1970s is thought to suggest that the wasp
may be a recent colonist.
Ectemnius sexcinctus (Fabricius) (Notable B) is associated with dead
wood fully exposed to the sun. The nest cells are stocked with large
flies, mainly Syrphids such as Scaeva pyrastri and Syrphus ribesii (Falk,
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