Invertebrate survey at Gunpowder Park, the former Royal Ordnance Site in the Lee Valley
morio being the probable host species. There are scattered records in Essex, mostly from the East
Thames Corridor. The larvae of S. niger use the nest and larval food of the host.
Pompilidae Arachnospila spissa Local, Essex Red Data species, Essex Threatened
The species was found in Area D. It is a medium-sized ground-nesting spider-hunting wasp which
is widespread and locally common. There are few records in Essex, mostly near the Thames in the
south of the county. It has been found in a variety of habitats on various soils in well-vcgctatcd
places including woodland. The wasp has been observed to attack large lycosid spiders like Alopecosa
pulverulenta whilst the spider is in its burrow guarding its egg sac (Day 1988). The spider is
paralysed before oviposition and the burrow entrance blocked with vegetable detritus.
Pompilidae Priocnemis agilis Notable/Nb, Essex Red Data species, Essex Threatened
The species was found in Areas B and C. It is widely recorded in the southern half of England and
is also known from south Wales. It is very local with few recent records, suggesting a general
decline, although the wasp has been recorded from a number of sites in Kent since 1981 (Falk
1991b). There are very few records in Essex, although it has been found in numbers at some sites.
It is typically encountered in dry, open, grassy situations such as sunny banks and south facing
slopes. Nothing seems to be known about its nesting habits, but there is a prey record for a Drassodes
species. Adults can be found visiting the flowers of Umbellifers such as Carrot.
Sphecidae Crossocerus cetratus Local, Essex Red Data species, Essex Threatened
The species was found in Area B. In Essex the wasp is scarce, and there are only a few scattered
records in the west of the county. It nests in dead wood and is a species of mature woodland.
Unfortunately the dead and diseased trees have been removed from the area where flie wasp w as found.
Sphecidae Didineis (Alysson) lunicornis Notable/Na, Essex Red Data species, Regionally Important
The species was found in Area C. This is a scarce species of southern England. Until 2000. when
the wasp was found in numbers at Rammey Marsh, all modern regional records of Didineis lunicornis
had been coastal or close to the Thames. It is strongly associated with the deep dessication cracks
that appear on clay or clay-rich ground during the summer months. Many records relate to soft rock
cliffs, whilst inland records include unimproved grasslands (especially south-facing slopes),
woodland rides and clearings, and revegetating quarries (Edwards & Telfer 2001).
Sphecidae Ectemnius lituratus Local, Essex Red Data species Essex, Threatened
The species was found in Areas B and D, where it was present in numbers on the umbels of Angelica
and Carrot. Most records of this wasp arc restricted to southern England south of a line between the
Bristol Channel and the Wash. In Essex it is scarce, with very few records in the w est of the county.
It occurs ill a variety of habitats, but perhaps especially woodlands. It is typically encountered
around dead wood, timber and Umbellifer flowers (Edwards 1998).
Sphecidae Nysson trimaculatus Notable/Nb, Essex Red Data species, Regionally Important
The species was found in Areas B and D. The wasp is widely distributed in the southern half of
England, and nearly all Essex records are in the East Thames Corridor. It is a cleptoparasite of the
wasp Gorytes quadrifasciatus and G. bicinctus and is recorded from a variety of open habitats on
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Essex Naturalist (New Series) 21 (2004)