Chrysura radians (Harris) (Hymenoptera: Chrysididae), a cuckoo-wasp new to Essex
ADRIAN KNOWLES
12 Blackbrook Road, Great Horkesley, Colchester C06 4TL
On 13 June 2000 a. single specimen of this striking cuckoo-wasp was collected outside the visitor
centre of the Essex Wildlife Trust's Fingringhoe Wick nature reserve. Ironically, it was not recorded
during the author's extensive survey work on the Hymenoptera of the reserve, but idly swatted from
a dead tree trunk whilst waiting to lead a guided walk around the reserve!
C. radians is one of the small, metallic green and red Chrysid wasps which are often seen hunting
over dry, dead wood, fence posts and even telegraph poles in search of host nest cells to parasitise.
It looks superficially like one of the wasps of the genus Chrysis but it is easily distinguished from
this taxonomically difficult group by the lack of stout teeth along the posterior margin of the third
abdominal segment. Morgan (1984) states that this species is a cleptoparasite of wood-boring bees
of the genus Osmia and possibly O. leaiana (Kirby) (Megachilidae) in particular. A megachilid bee
was observed prospecting over the dry trunk at the same time, but eluded capture and identification.
Reference
MORGAN, D. (1984) Cuckoo-wasps (Hymenoptera, Chrysididae). Handbooks for the Identification of
British Insects Vol. 6 Part 5.
Odynerus simillimus Morawitz, F., 1867, rediscovered in Essex
PETER HARVEY AND DAVID SCOTT*
32 Lodge Lane, Grays, Essex RM16 2YP
* Ford Farm, Brightlingsea, Colchester, Essex CO7 0SA
Odynerus simillimus is a Eumenine wasp that was considered extinct in Britain until its rediscovery
in 1986 in Norfolk (Archer 1989). The wasp is listed as Extinct (RDBK) in Shirt (1987), but Falk
(1991) provisionally places it in the Endangered (pRDBl) category. It was described from Russia
(Saratov) and, apart from British specimens, the species is known only from a few others in western
Europe (Richards 1980).
The only other published British records are from North Essex in the Colchester region that date
back to the end of the 19th Century and the start of the 20th Century. Both sexes are recorded (as O.
reniformis) 'at Colchester' by Harwood (1902), who also refers to a single specimen previously
being taken by the Harwoods. Nicholson (1928) evidently uses these records to describe O. reniformis
as 'scarce; Colchester district' and O. simillimus as 'very rare; Colchester (W.H. Harwood) and St.
Osyth (B.S. Harwood)'.
It was therefore very exciting for the first author to receive by post a female O. simillimus in August
2000. On 6th August David Scott had seen a possible female at Alresford Creek, flying around nest
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Essex Naturalist (New Series) 18 (2001)