ESSEX LEPIDOPTERA
41
The pen nevertheless was persistent in sitting on the eggs, and five cygnets
were hatched, one soon disappearing. The edges of the pond were cleaned out
in 1949, and owing to the wet winter and spring there was very much more
water in the pond in June 1951 than a year earlier. The pond is particularly
open to the force of southerly winds. Some of these factors possibly played
their part in the occurrence.
J. Ross
"Hovers" or floating islets of reed (Phragmites communis Trin.) mixed with
other vegetation occur in the Broadland district of Norfolk occasionally,
usually after a spell of low water followed by a fairly sharp rise. It is possible
that the occurrence of frost assists in the process. Such hovers on the Broads
often float for considerable distances and steps are taken to stake them in to
the rond to avoid the danger of such large masses of floating vegetation chok-
ing the narrow waterways and bridges. That similar factors have operated in
this case is not to be doubted. The water level in the pond has been much
higher this spring and the local weather report of the Chingford recorder
shows that in early June there was a spell of prolonged south to south-east
winds. After this strange removal the cob had a very busy time patrolling
the shallow stretch of water between the sitting pen and the nearby bank.
B. T. Ward
Essex Lepidoptera in 1951
BY H. C. HUGGINS, F.R.E.S.
As in the country generally, Lepidoptera have been rather scarce and
difficult to get in Essex in 1951. Migrants have been by no means absent,
but, as far as my personal experience goes, have been in small numbers.
I saw only two Clouded Yellow butterflies (Colias crocea (Fourcr.)) in all,
both males and both flying down this road in Westcliff-on-Sea, one on 2
August and one on 20 October. The Pale Clouded Yellow (C. hyale (Linn.))
was represented by two males only, both on lucerne at Battlesbridge on 14
September when I was shooting. Although both insects have undoubtedly been
very scarce locally, as I usually see a fair number when shooting, I have not
been able to do my usual systematic search of the lucerne fields between here
and Burnham as I am without a car at present.
Sugar at only a short distance from my house has produced several sur-
prises. Amongst these have been Vine's Rustic (Caradrina ambigua (Schiff.)) on
3 and 8 September, the White Point (Leucania albipuncta (Schiff.)) on 13 Sep-
tember, the Small Mottled Willow (Laphygma exigua (Hubn.)) on 10 September
and, best of all, a variety of the Angle-shades (Phlogophora meticulosa ab.
roscobrunnea) on 8 September. This lovely form, originally described by
Warren from the Azores, is apparently very scarce in this country. Its distinc-
tive feature is the complete absence of any greenish colour, the markings being
of a bright reddish-brown on a reddish-cream ground and the whole surface
flushed with rose. It seems to me just possible that the insect may be a migrant
as it was on the same row of trees as the others.
The Death's-head Hawk moth (Acherontia atropos (Linn.)) has been with us