Langton, P.H. & Pinder, L.C.V. 2007. Keys to the adult male Chironomidae of Britain and Ireland. Vols. 1 & 2. Freshwater Biological Association, Scientific Publication 64, pp. 239 + 168. ISBN 0-900386-75-6. - Review printed in Internat. Rev. Hydrobiol. (In press).

The Keys to the adult male Chironomidae of Britain and Ireland from Langton and Pinder 2007, FBA, Scientific Publication Nr. 64 is proposed as a new edition of the well known 1978 Pinder's publication A key to the adult males of the British Chironomidae (Diptera), FBA, Scientific Publication Nr. 37.

This new edition is however much more than a simple re-edition since it includes an additional 152 species occurring in Great Britain and Ireland, 16 newly described species and updated synonymy or species names according to current approved nomenclature. The key couplets and drawings for species considered in the 1978 edition have also been enriched. Thus, with now a total of 591 species considered, the use of the key largely goes beyond the borders of Ireland and Great Britain, since it addresses a substantial part of the Palaearctic fauna.

The structure of the book into two volumes, one with general information and keys (Vol. 1) and one with hypopygium drawings (Vol. 2) has been preserved by the authors, and special attention was given to linking the contents of both editions. Nevertheless, extensive new and updated information and additional drawings makes the new key more effective to use. Hence, volume 1 includes an introductory chapter, which gives general information on classification and morphology of the adult males, and forms the bridge between the differing terminologies used in the two editions. This is followed by a method chapter, which gives advice on how to collect, rear, preserve and mount chironomid imagines. A totally new chapter named "Notes on the use of the keys" is next included, which gives a list of considered genera, the number of species treated for each genus and page references to the corresponding key couplets. The body of volume 1 consists of the 9 keys split into 2 different chapters. One is dedicated to the key to subfamilies and one to the key to genera and species in the 8 subfamilies, each being treated in a separate section. Here, many new drawings illustrating morphological characters have been added for each species, cleverly placed on the page facing the relevant couplet. Page numbers referring to specific definitions in the "Morphology" section of the introductory chapter are also usefully given. At the end of volume 1, the authors provide updated literature compiled in the "References" chapter as well as an index of species pointing both on key couplets and hypopygium drawings.

Volume 2 provides high quality drawings of hypopygium for each species, and an appendix with the descriptions of 16 additional last-minute newly-described species for Ireland and Great Britain, which could not be included in the almost-ready version of volume 1 at the time of publication.

Finally, the revision of the 1978 Pinder's key to the adult males of British Chironomidae certainly appears as an acquisition that cannot be ignored by beginners or even experienced chironomid workers. I am glad to add, convinced of the shared enthusiasm of my colleagues, that we have been waiting for this new edition for a long time. Thanks to the authors.

Xavier-François GARCIA