PREFACE. VII 



years and by many persons, but having never been fully revised by him 

 have an unequal value. It was impossible, from their multitude and 

 the vast labor involved, to subject them to a critical examination, so 

 that while I have given them as found, it is only justice to the source 

 from which they caine to make this explanation. 



Through the intervention of Mr. E. C. Rye, of London, who himself sent 

 me various memoranda of omissions from previous lists, I received a man- 

 uscript catalogue of genera proposed in diptera, including their variations 

 in orthography, prepared and forwarded to me by Mr. G. H. Verrall, of 

 Newmarket ; the number of these, reaching several thousands,* would 

 surprise even a specialist in that group. Free use has been made of this 

 list so generously offered, and every name not previously recorded will 

 be found entered in the body of the Supplemental List. The list did 

 not contain complete references, but, in general, only indications of 

 author and date; fuller details, however, were in some instances fur- 

 nished by Mr. Verrall on application. 



Of other lists supplied by specialists in their own departments, I must 

 express my very great obligations to Mr. J. Bigot, of Paris, who kindly 

 sent me detailed references to three hundred and eighty-five genera of 

 diptera, referred to neither by Agassiz nor Marschall, bringing the list 

 down to May, 1879. To Capt. W. H. Dall, of the United States Coast 

 Survey, I am indebted for a vast number of memoranda of various kinds 

 upon mollusca, including a complete list of his own genera, besides 

 many corrections made upon the proofs of my work submitted to him ; 

 these are all made with his usual care and precision. The entries re- 

 ceived from Mr. Waterhouse, of the British Museum, to which allusion 

 has been made, have an especial value, since nearly till the references- 

 obtained by him from secondary sources have received his careful veri- 

 fication, and the list was made up of omissions from previous records j 

 his list and Mr. Ball's have been, after those obtained from Mr. Agassiz 

 and Mr. Verrall, perhaps the most extensive of all. I have received 

 also the very welcome and generous assistance of Mr. W. H. Dalton, of 

 H. M. Geological Survey, London, whose special work on the Geological 

 Record t enabled him to send me an extensive list of overlooked genera 

 of fossil animals, which were the more desirable from their having been 

 so generally neglected since Agassiz's time. Similar aid was received 

 from Mr. W. F. Kirby, of the British Museum, who sent me a long array 

 of names in lepidoptera, mostly of recent years, which his labors on the 



* 111 February, 1882, Mr. Verrall wrote me that this list, which when sent to mo con- 

 tained about 4,400 names, of which he had seen the original references to all except 

 about 290, now contained 4,900 names ; of these he considers fully one-third as only 

 misprints or misspellings, which had been collected for index purposes, erroneous 

 forms being frequently misleading and troublesome. 



t The geological record for 1874 [-1877]. An account of works on geology, miner- 

 alogy, and palaeontology published during the year. Edited by William Whitaker. 

 8. London', 4 vols., 1875-1880. The last two volumes add to the title: With sup- 

 plements for 1874-1875 [1874-1876]. 



