r^Aßy [ ti' miùmsë mm «:;^ A REVISION OF THE PALAE ARCTIC SPECIES OF THE NIGRIPES GROUP OF THE GENUS AGROMYZA FALLEN (DIPTERA, AGROMYZIDAE) G. C. D. GRIFFITHS, B.A, F.R.E.S. 88:1, Ai'ondale Avenue, East Barnet, Herts., England Contents Introduction HI Characterisation of the group 112 Group of nigripes Meigen 112 Group of ambigua Fallen 113 The nigripes group outside the Palaearctic region 114 Comments on earlier treatment of the group 114 Phylogeny 115 Host relationship 117 Keys for identification 119 Adults 119 Larvae 121 Descriptions 122 Parasites 159 Acknowledgements 164 Summary 164 References 165 Introduction The species of the nigripes group of the genus Agromyza Fallen are exclusively feeders on Gramineae, including the cultivated forms. They often come to the notice of the applied entomologist, and there are numerous references to them in the literature. This paper, although written primarily from a taxonomical point of view, is intended also to assist the work of the applied entomologist. Past work in this field has sometimes been confused through the author failing to realise that he was dealing with more than one species with different life-histories; the host-relationships too have not hitherto been very clear. It is hoped that this paper will provide a sound taxonomie basis for future work. The need for a complete revision of the group has been apparent for some time. The external characters of the adult do not provide many good specific differences, and it was clear that an attempt to use the characters of the male genitalia for classification needed to be made. These had not been employed by Hendel (1931). Also the larval key hitherto in use, originating from de Meijere (1943), has proved to be almost unworkable. I have decided to make a fresh start with a new key. The terminology used for the external morphology of the adult in this paper is 113
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