PTEROMALIDAE OF N.W. EUROPE 5 



of those described by Forster, whose collections were not available for study, and 

 those of Nees and Ratzeburg whose collections were for the most part destroyed by 

 military action during World War II). Therefore the synonymy presented here 

 depends very largely upon the direct comparison of type-specimens, which has not 

 been attempted before on a comprehensive scale. Walker's types have been 

 particularly valuable because I have been able to compare with them large quantities 

 of fresh material which I have collected during the past 20 years in the country in 

 which Walker himself collected (often in the type-localities), as well as much material 

 collected by others. This has, in the case of the majority of species, made it possible 

 to find a virtually exact match for type-specimens and to study the range of varia- 

 tion without having to worry unduly about the distracting features of geographical 

 variation. The same procedure has been applied to the species described by 

 Thomson, using the fine assemblage of fresh material collected in Sweden by Dr. 

 J. F. and Mrs. D. M. S. Perkins, and other material which I collected there in 1959. 

 The present study concerns primarily the fauna of the north-western part of 

 Europe, especially the British Isles and Scandinavia. Some species and genera 

 from other parts of Europe, and even from other regions, are included where this is 

 considered expedient for special reasons. Thus all the genera so far described from 

 Europe have been included in the keys to genera for the sake of completeness. It is 

 therefore hoped that the revision may be of rather more than local interest. 



ACKNOWLEDGEMENTS 



Dr. Z. Boucek (Narodni Museum v Praze, Prague) has greatly helped me by his 

 constant interest, loans and gifts of specimens, and by testing and commenting on 

 some of the keys. I wish to offer him, and the other persons mentioned, my sincere 

 thanks for help in various ways. I owe a special debt to those in charge of important 

 collections, many of whom have showed extreme patience in forbearing to redeem 

 loans of several years standing, without which the work would have been impossible. 



Mr. Hugo Anderson (Universitetets Zoologiska Institutionen, Lund), Dr. R. R. 

 Askew (Manchester University), Dr. Bachmeier (Zoologischer Museum des Bayer- 

 ischen Staates, Munich), Dr. A. Bakke (Oslo), Dr. Max Beier (Naturhistorisches 

 Museum, Vienna), Dr. B. D. Burks (U.S.D.A., Washington), Dr. M. F. Claridge 

 (University College of South Wales, Cardiff), Mr. B. J. Clifton (Library of the Entom- 

 ological Dept., British Museum (Nat. Hist.)), Dr. V. Delucchi (F.A.O., Rome), 

 The Director, and Miss L. Gombrich (Commonwealth Forestry Institute, Oxford), 

 Mr. J. P. Doncaster (British Museum (Nat. Hist.)), Dr. J. Erdos (Tompa, Hungary), 

 Dr. Ch. Ferriere (Museum d'Histoire naturelle, Geneva), Dr. Max Fischer (Natur- 

 historisches Museum, Vienna), Mr. G. R. Gradwell (Hope Department, Oxford), 

 Mr. K.-J. Hedqvist (Skogshogskolan, Stockholm), Dr. A. Hoffer (Prague), Mr. S. 

 Johanssen (Universitetets Zoologiska Institutionen, Lund), Mr. G. J. Kerrich 

 (Commonwealth Institute of Entomology), Prof. C. H. Lindroth (Universitetets 

 Zoologiska Institutionen, Lund), Dr. L. Moczar (Hungarian Natural History 

 Museum, Budapest), Dr. A. Neboiss (National Museum of Victoria, Melbourne), 

 Dr. M. N. Nikol'skaya (Zoological Institute, Academy of Sciences of U.S.S.R., 



