PREFACE. V. 



for the facts from which our Locality lists, Times of Appearance, and 

 details as to Habit and Habitat have been compiled ; to others we are 

 indebted for a generous expenditure of time in procuring material, and 

 for the loan of interesting and important specimens. Without this help 

 we need hardly say much of the minutiae of this work could not possibly 

 have been got together. 



It may also be urged that it was unnecessary to enter so fully into 

 historical detail, and that our book here (as well as in the synonymy 

 used) shows within itself the mode of evolution of our work. We 

 suspect that this has its advantages, and will enable students to grapple 

 more readily with the difficulties that we had to meet as our work 

 progressed. The study of an obscure and difficult group, such as the 

 Psychids undoubtedly form, necessitates a clear understanding of the 

 work already done before any advance can be made, and one is obliged 

 to check with specimens almost every fact as one goes on, or one would 

 find oneself admitting very different descriptions as of the same species 

 — two, three, and even more species having frequently been described 

 under the same name by different authors. Everything that we con- 

 sidered would help to make clearer the facts that had to be elucidated 

 has been discussed, and we claim to have given lepidopterists an 

 amount of material that will enable them to prosecute the study of 

 this group, at least with some greater probability of success than has 

 been possible hitherto. At the same time the true relations of the various 

 Psychic! groups had never been previously thoroughly investigated, and 

 hence, as our studies proceeded, and the facts about the various species 

 accumulated, generalisations became possible which could not have 

 been formulated when the work was begun. We can only hope that 

 our account of these interesting insects will entice many lepidopterists 

 to study them, and one may safely prophesy that, with more workers, 

 many new facts relating to them will soon be discovered. 



What is true of the gradual development of our own views of this 

 group as the work progressed, is equally true of our usage of the names 

 (particularly generic names) that we have felt compelled to adopt. 

 We assumed primarily that Heylaerts' work (Ann. Soc. Ent. Belg., 

 1881) dealt with the nomenclature on sound lines ; but we soon dis- 

 covered as we went on that he had quite overlooked much of the 

 generic nomenclature of his predecessors, and that many (indeed, 

 most) of his new names fell before those of earlier authors. The 

 catalogue on pp. 432-434 shows our final conclusions on this subject. 



It would be unjust to the earlier students of this superfamily were we 

 not to acknowledge our indebtedness to their pioneer work. Beaumur, 

 Zeller, Guenee, Bruand, Speyer, Hofmann, Standfuss, and Heylaerts 

 have been laid freely under contribution, often for quotation, some- 

 times for criticism, but we believe always with due acknowledgment in 

 the first case, and we trust justly and with due cause in the second. 



The work connected with the Lachneids has been comparatively 

 straightforward. The difficulty here has been in some cases to separate 

 the wheat from the chaff, and much material has had to be sifted and 

 much rejected. Many authors have dealt with the group incidentally, 

 but to Aurivillius, who had largely cleared the way as to the synonymy, 

 and given us a right appreciation of the superfamily, our thanks are 

 especially due. The life-histories, however, have had to be done de 



