Colin W. Plant published a paper in the journal Transactions of the Hertfordshire Natural History Society 2004, 36(1): 47 - 68.

Its purpose is to encourage people to go out and look for the missing species in Hertfordshire and some notes on how to do this are provided for many species. The abstract is below and there are links below to an abbreviated version of the full paper

Abstract (reproduced un-altered)

Of the all-time total of 1,536 moth species recorded in the English Vice County of Hertfordshire (VC 20), just over one fifth (22%) have not been recorded in the ten years since 31st December 1994 in spite of an intensive recording effort. This total of 334 lost moth species – comprising 227 “micros” and 107 “macros” – is analysed. The absence of 68 of these is judged not ecologically important, because they are either rare immigrants, vagrants or have arrived in the past only with human assistance. The taxonomic status of two species, and the reliability of records of two more, is questionable. However, 112 species are judged likely to be extinct in the County; these species are listed. The failure to record a further 150 species in the past ten years may reflect a need for specialist recording; these species are discussed briefly and hints for finding them are presented.

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