PRESENT VALUES OF PRINCIPAL WORKS ON LEPIDOPTERA. 223 



had to refer to catalogues dating from 1912 or 1913; prices 

 since then have advanced 20 or 30 per cent. Whether these 

 advances are permanent time alone can show, hut it is 

 certain that the older and rarer books are getting scarcer every 

 year by absorption into the libraries of museums and other 

 public institutions, both in this country and abroad, and espe- 

 cially in America. As I have previously pointed out on page 92 of 

 the present volume, the result of recent sales by auction has been 

 extremely disappointing. Entirely through the want of interest 

 displayed by lepidopterists the dealers have been allowed to reap 

 rich harvests, and have obtained extremely valuable books for 

 a mere song, thereby realising in a few days a profit of, in some 

 cases, 2000 or 3000 per cent. 



In dealing with the books seriatim it will perhaps facilitate 

 reference and lead to greater clearness if I arrange them alpha- 

 betically and keep those issued in each country together. But 

 before doing this I would like to refer to two works of exceptional 

 utility. 



It is obvious that the first need of a student of the Lepidop- 

 tera is an efficient catalogue that will post him up in the 

 particulars of books that have been published, and also of one 

 that will give the references to everything of importance that 

 has ever been written about each species. 



The only book as a single volume, or rather two volumes usually 

 bound together, that has ever been written on the bibliography 

 of the science, is Bibliotheca Entomologica, by H. A. Hagen 

 (Leipzig, 1862), an excellent and careful work that gives par- 

 ticulars of all works or papers of importance that had been 

 written to that date. It is not an expensive work. My copy 

 cost 15s. a few years ago ; it is now priced at 20s. 



There are, of course, the volumes of the Zoological Record, 

 which I will deal with later on. 



The bibliography of each species is described in Catalog der 

 Lepidopteren des Palaearctischen, by Staudinger and Rebel, the 

 1901 edition (Berlin: R. Friedlander & Sohn), published at 12s., 

 and probably still to be had from the publishers at about that 

 figure. This is absolutely the most important book in existence 

 for a student of the Lepidoptera of this region or of any part of 

 it ; one cannot move without it. There are errors, of course, 

 plenty of them, but it gives us the references of the most impor- 

 tant works dealing with the almost 10,000 species inhabiting 

 the region. There are other catalogues in process of issue, but 

 apart from the fact that they are very expensive, they are too 

 fragmentary at present to be of much service to the student. 



An extremely useful article entitled The Present Prices of the 

 Older Works on British Entomology, by Mr. South, appeared in 

 vol. xxxi, pp. 261-264, of this magazine; to this I refer my readers. 

 {To be continued.) 



