LEPIDOPTERA IN EAST ESSEX IN 1950 293
LEPIDOPTERA IN EAST ESSEX IN 1950
BY A. J. DEWICK
The following notes on Lepidoptera in east Essex in 1950 refer in the main
to the migratory species. All the moths were specimens taken in a light-trap
operated at Bradwell-on-Sea all night from 15 April to 15 November.
The first Silver Y (Plusia gamma (L.)) appeared on 31 April ; the species
later became very abundant, over 35,000 being recorded in the season.
The Red Admiral (Vanessa atalanta (L.)) and the Painted Lady (V.
cardui (L.)) arrived in May as usual, a single atalanta on 1st and three cardui
on 22nd. Taking the season as a whole there were four atalanta to one
cardui, almost precisely the reverse of 1949.
June produced some of the less-common migrants, the first Pale Clouded
Yellow (Colias hyale (L.)) being seen on the 6th, and on the same day,
which was very hot and sunny with a light south-east breeze, a butterfly that
must have been the Swallowtail (Papilio machaon (L.)) was seen by several
men working on the sea-wall near St. Peter's Chapel. It was first noted
resting on a piece of wood ; on being disturbed it flew away rapidly to the
north-west, so it may well have belonged to the continental subspecies
bigenerata. This seems to be the first record locally since 1945, when four
specimens, also flying north-west, were seen.
A single female Clouded Yellow (Colias crocea (Fourcr.)) was noted
on the 13th, no more being seen for over a month. An unexpected visitor
to the light-trap on the morning of the 25th was a fine specimen of the Striped
Hawk moth (Celerio livornica (Esp.)), unfortunately a male. The same day,
in two small fields of lucerne, eight C. hyale were noted ; five were females
busy ovipositing.
The first few days of July were dull, and marked the beginning of the end
of any real summer weather; really good days for observing butterflies being
few and far between after this. However, a very considerable immigration
of P. gamma must have reached Essex about this time, the catch in the light-
trap jumping from three on the 3rd to 734 on the 4th and to 2469 on the 5th,
including a single specimen of the uncommon Small Mottled Willow (Lap-
hygma exigua (Hubn.)). The peak was reached on the 6th, with at least
5636 P. gamma. After a drop to 1688 on the 7th, numbers rose to 3372 on
the 8th, finally falling to a more normal 206 next day.
The second broods of V. atalanta and V. cardui emerged about mid-July ;
the former being seen regularly until the cold weather in mid-October ;
the latter petering out in early September. C. crocea appeared suddenly
on 18 July, ten specimens being seen in one lucerne field under rather in-
different weather conditions, and it was pretty general in the district until
early September ; fresh specimens appeared again from 5 October, perhaps
another emergence, but the weather was very bad and no large numbers
were seen. The total noted in the season was 203 with only one ab. helice,
which may be compared with 1075, including 29 helice, in 1949.
On the last day of July a full-fed larva of the Death's Head Hawk moth
(Acherontia atropos (L.)) was found crawling on a road some distance from
the nearest potatoes ; it proved to have been "stung." Larvae were reported
from all over the area during August and seem to have been general in south-
east England.
The second brood of C. hyale began to emerge on 8 August, and it was not
uncommon for the rest of the month. The Convolvulus Hawk moth (Herse
convolvuli (L.)) appeared in the light-trap on the 10th, a total of eighteen
occurring between that date and 20 September, when four arrived together.
The weather during September was very poor for butterflies but large
numbers of moths continued to visit light. A male of the rare Delicate