the names of the genera and that of thi^ collaboratui at the heatl of the pages. As the anangenient of 

 the text is very clear, I considered it permissible to restrict to the utmost the nomenclature on the plates 

 and therefore placed, beneath each figure only the specific or varietal name. We have thus avoided the 

 inconvenient method of numbering every figure, which might have proved a calamity in our case, con- 

 sidering the large numl)er of figures on a plate, some plates containing no less than 70 — HO figures. More- 

 over, the figures are nearly always arranged in rows and, as far as technical leasons did not prevent it, 

 in the same order as the text. This mechanical arrangemeiit, in connection with the numerous half- 

 figures, renders the whole rather inartistic and very monotonous; but it seemed to us advisable to adopt 

 this plan, because we aimed in our work at lucidity and handiness rather than at beauty and elegance 

 and had no intention of blinding the public by an artistic make up of the plates to the detriment of . 

 usefulness. 



The same point of view has been paramount in the reproduction of the figures. Our purpose 

 was to issue the most completely illustrated work which has ever been published, and to offer it at such 

 an unprecedentedly low price that it would be in the reach of everybody notwithstanding its con- 

 siderable size. If nevertheless in several independent reviews many figures have been called the most 

 accurate ones hitherto produced, this success is due on the one hand to the perfection of modern tech- 

 nique, and on the other to the efficiency of the firms to which the reproduction of the plates was en- 

 trusted, and to whom the best thanks of the editor are here expressed for the great pains they have 

 bestowed on the work. 



Next to cheapness, rapidity of pubhcation appeared to us the must important point. All similar 

 serial works and even many of lesser size have hitherto been issued with increasing delay, or their puljlic- 

 ation has been interrupted or altogether discontinued. We decided on the contrary to issue the numbers 

 at first slowly .and later at shorter intervals, and to fix definitely the end of 1912 as the time for the 

 completion of the entire work. The first number appeared in October 1906 and to-day, after a lapse of 

 liardly 80 months, the first volume is in the hands of the public, 100 numbers having been issued, about 

 l:-50 being ready for publication and many more approaching completion. 



It was only possible to attain this result with the kind and willing assistance, either asked for or 

 Aolunteered, of a large number of Lepidopterists. Not until the most important collectors of the world, 

 foremost among them the Hon. L. W. Rothschilr, of Tring, permitted their valuable treasures to be used 

 as originals for the plates, was the publication of the work at all feasible. The types in the British 

 Museum, especially those of Hewitson, and many from other important collections in England, have most 

 faithfully been copied by Mr. Horace Knight; those in the Paris Museum by Monsieur Pou.jade. Through 

 the courtesy of Messrs. Jordan and Warren we have received many specimens from Tring; Monsieur Sergei 

 Alpheraky, of St. Petersbourg. and Herr Chr. Aurivillius, of Stockholm, had the kindness to send contri- 

 l)utions. We are indebted to Mr. W. F. Kirby, of London, for much important information, and to 

 Sir George Hampson for so very kindly showing me round in the enormous collection of the British 

 Museum. I inspected collections in South America under the able guidance of Messrs. Carlos Berg and 

 Emilio A. Goeldi, and Professor von jHERiNtt, with great amiabihty, even entrusted some of the treasures 

 of the Museu Paulista to a voyage across the Atlantic. In Asia I was especially assisted by Messrs. Green 

 and Mackwood in Ceylon, Skektchley at Hongkong, Watson, Fritze and Schedel in Japan. Messrs. Wm. 

 McLeay', Sy'dney Olliff and Masters gave me many facilities when inspecting Australian Museums, and 

 Messrs. Packard and Ellison Smy'th as well as Radcliffe Grote presented me with notes on important 

 observations and with specimens from North America. 



German and Swiss Museums also have taken much interest in the undertaking. In the first place 

 my thanks must be addressed to the Kongl. Museum in Berlin, whose director. Professor A. Brauer 

 allowed me to make as much use of the collection as the rules permitted, and where Herren F. Karsch 

 and Grunberg kindly assisted me in selecting the specimens. The Senkenberg Museum at Frankfurt a. M. 

 and the Federal Entomological ^luseum at /iirich also supported me, the latter through the courteous 

 office of Herr Max Standfuss. Moreover, valuable assistance has been rendered by a great many private 

 collectors, whom we have not room enough to enumerate. First of all we have to mention Herren Bang- 

 Haas sen. and jun., who were of invaluable help to me with their abundance of material, unique on the 

 Continent. This firm, whose influence with regard to the role which Germany plays at the present time 

 in Lepidopterology cannot he too highly appreciated, has sacrificed unselfishly time, labour and specimens 

 in order to render the work more complete, a large proportion of the new forms proposed in this work 

 being provided from its inexhaustible store by this firm of world-wide name. Also Herren Burgeff, of 

 Geisenheim, Jacobs of Wiesbaden, Geest, of Freiburg i. B., Nassauer, of Frankfurt, Ney and Pungeler, of 

 Aachen, and Courvoisier, of Bale, entrusted me from their special collections with rare or unique specimens 

 for figuring, and the two last-named gentlemen undertook, moreover, the trouble of revising part of the 

 manuscript. Herr AV. Leoniiardt, of Frankfurt a. M., with great liberahty, put at my entire disposal a 

 collection of notes on L v c a e n i d a e which it had taken decades to collect. However, it 



