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Aquatic Hemiptera in the Chelmsford Area
BY P. M. HAMMOND
A number of water-boatmen and other aquatic bugs have been col-
lected during the past year or so, incidentally, while collecting
aquatic Coleoptera, in the Chelmsford district. They have been
obtained from a number of varied aquatic habitats mainly in Great
Baddow and Galleywood. Naturally, most of the bugs collected are
common species, but the occurrence of some of the species is of interest.
NOTONECTIDAE
Notonecta glauca L. A common species and, as expected, found in many
of the habitats. N. maculata Fab. The only species found in two water-
troughs in Gt. Baddow where it has been abundant for several years.
One specimen, possibly a stray, at Great Baddow, in a pond. This is an
interesting species as it requires a hard substratum on which to deposit
its eggs and. although fairly common in the south of England, it does
not appear to have been recorded from Essex.
N. viridis Delcourt. Not found in the Chelmsford area, but three
specimens obtained from Northey Island, 30th October, 1958. A brackish
water species, but again does not appear to have been taken in Essex.
CORIXIDAE
Corixa punctata Illiger. and C. sahlbergi Fieber. Found in every
habitat and very common in most.
C. nigrolineata Fieber. Very common where it occurs.
C. praeusta Fieber. Common in one pond at Galleywood and found
on odd occasions in Gt. Baddow.
C. moesta Fieber. Fairly common in one pond at Galleywood; Macan
(1956. A Revised Key to the British Water-Bugs) gives C. moesta as
"rather rare", but it is also recorded in 'The Victoria History of Essex',
and by C. Nicholson (Essex Naturalist, Vol. XXI, p.169) for Essex.
C. dorsalis Leach. Gt. Baddow and Galleywood. Macan gives it as one
of the commonest species, but I can find no record of its occurrence in
Essex.
C. limitata Jaczewski. Galleywood and Gt. Baddow.
C. distincta Fieber; one from Gt. Baddow.
C. linnei Jaczewski; only one, a 9, from Galleywood.
C. affinis Leach; one, a ♂ from Galleywood, 28th February, 1959. A
rare species, apparently new to the county.
C. scotti D. and S., from gravel pits at Sandon; again no apparent
previous record for the county.
NAUCORIDAE
Ilyocoris cimicoides L. Only one; from a water-trough, Gt. Baddow,
1956.
PLEIDAE
Plea leachi MacGreg. Common in ponds with much duckweed in
Gt. Baddow.