Mathew are also present; in fact, there are few collections completely devoid of Essex material. The
Doubleday collection, potentially the richest, lacks data and is consequently useless as a source.
Where curation is complete, the specimens are grouped by counties and the extraction of records is
easy. However, in most cases this has not yet been done, the Essex specimens are scattered and, if the
moth is pinned low, the data label is obscured. Consequently in these cases the extraction of records is
far from complete and this should be borne in mind by any future researcher. Records from the
Passmore Edwards Museum have been communicated by C.W. Plant and B. McRitchie has kindly
supplied the records from the Mace collection at the Harlow Museum. The staff of the Colchester
Museum have also sent me their records. As far as is known, no other museum holds important Essex
material.
It will not have escaped the attentive reader that the sources mentioned so far account for open and
crossed squares on the maps but hardly at all for the solid dots which predominate. These have been
amassed as a result of intensive recording undertaken by a small band of Essex entomologists. As
soon as the scheme was launched, I prepared a set of maps giving all the then available records. At this
stage, the only post-Guide records were those from the butterfly atlas (Payne & Skinner, 1981), from
a card index compiled by the Colchester Museum to show the records made by the Colchester and
District Natural History Society and from a small number received by G.A. Pyman as
macrolepidoptera recorder for the county. To these were added the personal records made by
Mr Pyman and myself. These first maps showed very uneven incidence, there being many squares
without a single record. There were only 3,700 black dots, the butterflies accounting for 1,000 of
them. Copies of the maps were sent to potential recorders who were asked to fill the gaps and update
records. The response was good but at the end of the 1982 season the recording was still so patchy that
the Panel decided that at least another year was essential. I prepared and issued a new set of updated
maps. These indicated the under-recorded squares which were as far as possible allocated to the most
conveniently situated lepidopterists. Recording was thereafter better coordinated and produced better
results, as the following figures show.
End 1981 End 1984
Total number of black dots 3,707 16,050
Average number of dots per square 65 281
Average number of squares per species (post 1970) 6 27
Those who took part in the scheme have every right to feel gratified by their achievement so far, but
there is still a long way to go before the recording of the Essex macrolepidoptera can be regarded as
complete.
Although dot distribution maps give a good general picture, their weakness is that they do not
distinguish between the occurrence of a stray specimen and the existence of a vigorous resident
population. A map must therefore be interpreted in the light of the status summary. In one or two
cases, indicated in the text, a dot showing the location of a colony considered to be endangered has not
been entered on the map.
The symbols used on the maps are as follows.
□ Record made prior to 1960
◘ Record made 1960-1969
■ Record made 1970 onwards
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