The author desires here to express his thanks to Mr. Robert Adkin, F.E.S., for the loan of specimens of _L. coenosa_, _E. ilicifolia_, _D. harpagula_, _N. albula_, _N. centonalis_, _D. barrettii_, _D. cæsia_, _P. xanthomista_, _T. extrema_, _L. favicolor_, _L. vitellina_, and _H. palustris_. To Mr. Alfred Sich, F.E.S., for the use of drawings of the caterpillars of _D. tiliæ_, _S. fagi_, _L. bicoloria_, _P. ridens_, _A. auricoma_, _A. rumicis_, _A. aceris_, _N. brunnea_, _M. oleracea_, _A. tragopogonis_, _T. gothica_, and _T. incerta_. To Mr. H. L. Sich for the loan of drawings of the caterpillars of _D. euphorbiæ_, _D. galii_, _D. chaonia_, and _P. dictoea_. For the material figured on Plate 148, except the larva of _L. putrescens_, kindly sent by Mr. Walker, of Torquay, he is indebted to Mr. H. M. Edelsten, F.E.S. Except where otherwise mentioned, the illustrations of moths and caterpillars at rest are from photographs by "A Forester." To Mr. Horace Knight he is very greatly obliged for the care bestowed upon the drawings of ova, larvæ, and pupæ, the bulk of which were made from living examples; also the coloured drawings for Plates 1, 45, 63, 68, 73, 75, 80, 84, 90, 108, 119, 123, 140, 146, 149, and 153. The only figures copied from any previous publication are those of the caterpillars of _S. fuliginosa_, _D. sanio_, _D. pulchella_, _A. corticea_, _A. strigula_, _N. plecta_, and _N. augur_ (Wilson's "Larvæ Brit. Lep."); and among the moths, the varieties of _A. caia_; _D. mendica_ (4 Yorks.), Trans. Ent. Soc. Lond., 1889; _S. walkeri_, Curtis, and _N. subrosea_, Stephens. RICHARD SOUTH. * * * * * PREFACE TO THE PRESENT EDITION. A new edition of this volume having become necessary, it was deemed a fitting opportunity to bring the subject matter somewhat in line with our present knowledge of the Nomenclature, Habits, and Distribution of the Species considered therein. With this end in view, the new facts have been incorporated in the text so far as this was possible. Matter that could not be accommodated in this way has been presented in the form of an Appendix. The changes in the names of genera are not numerous, and in every case where such change has been made, the name used in the first edition has been placed in brackets--_i.e._ _Pieris daplidice_ of the 1st edition becomes in the present one _Pontia (Pieris) daplidice_. By this treatment it has been found convenient to utilise the old Index and, at the same time, to provide a Specific Index for those who prefer to consult the volume by its aid. * * * * * {1} THE MOTHS OF THE BRITISH ISLES. PART I. INTRODUCTORY.