The ground lackey (Malacosoma castrensis), a small member of the eggar family, has larvae which
feed in this country on various salt-marsh plants. Essex can claim to be the stronghold of this moth
which is to be found in Britain only along the coast from south Suffolk to north Kent Like the Essex
emerald it is not restricted to the seaboard on the other side of the North Sea where it occurs in woods
and on heaths. The gregarious larvae are a conspicuous sight on certain Essex saltings.
Essex is also one of the strongholds of a number of less restricted but still very local species. The
least carpet (Idaea vulpinaria) is in reality a small member of the group of moths known as the waves.
Its name derives from the dark central band on the whitish forewing which gives the insect the
superficial appearance of a diminutive member of another group of geometers known collectively as
the carpets. It is very local, being confined to eastern and southern England where its real stronghold is
said to be both banks of the Thames east of London. As far as Essex is concerned, this moth has
extended its range significantly in recent years and is now to be found along the coast and estuaries up
to Harwich as well as in a number of inland localities in the southern half of the county and
occasionally even further afield.
A moth which was once exceedingly local and rare in Essex and confined in Britain to the south-
eastern seaboard is the large thorn (Ennomos autumnaria), the largest British member of the 'thorn'
group and a striking insect with its rich ochreous colouration and scalloped wings. Harwood (1903)
knew only of single specimens from Shoeburyness and Harwich but in the intervening years the moth,
which is now widespread in all the coastal counties from Suffolk to Hampshire and is ranging further
inland, has become established at varying density in a number of widely scattered Essex
localities.
The sloe carpet (Aleucis distinctaria) is an undistinguished-looking, small, grey-brown moth which
flies in spring round blackthorn on which its larva feeds. Found locally from Hampshire to Suffolk and
westwards to Berkshire, it is probably as prevalent in Essex as in any county, although it seems to be
virtually confined to the eastern half.
A far more conspicuous insect than the last is the handsome and fairly large cream-spot tiger
(Arctia villica). With its white-spotted black forewings, black-spotted yellow hindwings and reddish
body it is instantly recognisable when it is disturbed from cover during the day. Its furry larva, which
feeds on a variety of low-growing plants, is also conspicuous. It is virtually restricted to that part of
England south of a line from the Severn to the Wash, and to south Wales, and has a preference for the
coast. In Essex it is widespread on the coast and estuaries but records from the interior of the county
are few and far between.
The diminutive rosy marbled (Elaphria venustula) is an attractive whitish moth with a pronounced
rosy flush when it is fresh. Its larva feeds on Cinquefoil and it frequents open woodland where bracken
is plentiful. It is an extremely local insect which is confined to Essex and a handful of sites in the
southern counties. Many years ago Epping Forest was a well-known locality for it and the reports that
one appeared there in 1983 for the first time in nearly a hundred years and another in 1984 are most
welcome. It still persists near Brentwood although parts of its former territory have been built over,
and is locally common on Danbury Ridge which must rank as one of its main British
strongholds.
The olive crescent (Trisateles emortualis), a delicate insect with wings of a soft brown colouration
crossed by white lines and which belongs to a group known as the 'fanfoots', is an example of a moth
long thought to be extinct in Britain which has been rediscovered after nearly a century. There were
four records in the mid 19th century- in Sussex in 1858, in Epping Forest in 1859 and again in 1870,
and in Oxfordshire, also in 1859 (Heath et al., 1983). Nothing more was seen of the moth until 1962
when it was found in the same part of Oxfordshire as in 1859 and proved to be established there. One
that appeared at Bradwell-on-Sea in 1970 was presumed to have been an immigrant, but it has since
been found to be a low-density resident of woodland in the north of Essex.
A moth which was at one time considered to be a rarity in Essex and elsewhere but which the
introduction of the mercury-vapour lamp has shown to be widely distributed at low to medium density
is the elegant black, grey and white alder moth (Acronicta alni). Since 1969 it has been found in 21
10km squares scattered throughout the county. The larva, which is also distinctive with its yellow-
marked, black body and long clubbed hairs, feeds on a variety of trees and shrubs despite the moth's
English name.
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