5
ESSEX LARGER BRACHYCERA DISTRIBUTION MAPS
Colin Plant is shortly publishing the third edition of distribution maps for the Larger
Brachycera. It includes all records received by him up to and including 26th October this
year, and collates and summarises all available data for the two vice-counties of South
Esex and North Essex in the form of ten-kilometre square dot-distribution maps.
The Larger Brachycera is a division of the true flies (Diptera). In the British Isles, this
involves the ten families Stratiomyidae (soldier flies), Xylomyiidae (= Solvidae),
Xylophagidae, Tabanidae (horse flies, cleggs, etc.), Rhagionidae (snipe flies), Asilidae
(robber flies), Therevidae (stiletto flies), Scenopinidae (window flies), Acroceridae and
Bombylidae (bee flies); all except the Xylophagidae are represented in the currently
known Essex fauna. Included are some of our largest and most striking flies.
Colin notes the distributions of some species are beginning to adopt a pattern.
Chloromyia formosa (Stratiomyidae) and Bombylius major (Bombyliidae) are evidently
widespread and common, though the latter species clearly dislikes the London region.
The coastal distributions of some species, most notably of Nemotelus notatus and
Nemotelus uliginosus (Stratiomyidae) are also fairly evident.
However the county remains very poorly recorded for the Larger Brachycera and even
common and widespread species are still not yet noted from every ten-kilometere square
whilst there are no records at all for any member of the Xylophagidae.
It is hoped that entomologists will be stimulated by the poor state of records in Essex to
increase their recording efforts. Colin emphasises that records are being kept on the basis
of one-kilometre squares, so that records are still wanted for all ten-kilometre squares.
If you would like a copy of the Essex Larger Brachycera distribution maps, please send a
large (A4) SAE with stamps for the second weight band (upto 100g) to Colin W. Plant,
The Visitor Centre, East Ham Nature Reserve, Norman Road, East Ham, London E6
4HN.
A NEW CHRYSID WASP FOR ESSEX
In June this year I took a specimen of the rare chrysid wasp Chrysis gracillima (formerly
Chrysogona gracillima) at an important site on Thames Terrace gravels at Chadwell,
South Essex. The species has a national Red Data Book status of vulnerable (RDB2) and
very few specimens have been taken in Britain. It has previously been found in Kent,
West Sussex, Surrey and Hampshire, three specimens being taken in consecutive years on
a dead tree near Winchester (George Else, personal communication). It is a parasitoid of
the larvae of other aculeates, possibly of the sphecid wasp genus Trypoxylon , which is
quite frequent at the Chadwell site. I am grateful to John Felton and George Else for
confirming the identity of the wasp.
Peter Harvey