GENERIC NAMES Ol BUTTERFLIES 15 



regarded by many authors, though erroneously, to invalidate the name concerned — 

 or names incorrectly regarded as junior homonyms of similar, though not identical, 

 names of older date. Tjype-species have now been selected for every genus found to 

 be without one. 



In the interests of nomenclatorial stability the general principle followed in making 

 these type-selections has been to secure that the generic names concerned should 

 become junior objective synonyms of available names of older date or, where this 

 was not practicable, junior subjective synonyms of such names. 



It was only when a type-species had been validly determined for every nominal 

 genus that it became possible definitely to establish which generic names were 

 available under the Law of Priority and which were invalid as junior objective 

 synonyms of names of older date. In the case of each name found to be objectively 

 invalid in this way, a brief explanatory note has been added to the text. 



V. DETERMINATION OF DATES O] PUBLICATION 



Throughout the whole of the XlXtli century students of the butterflies — and 

 indeed of the Lepidoptera generally were greatly handicapped by the almost total 

 lack of information available regarding the dates of publication of the principal 

 works of the German entomologist Jacob Hubner ol Augsburg and of the post- 

 humously issued supplements to certain of those works edited by his assistant I arl 

 Geyer. These works, which were published over a period of forty wars (1796-1838), 

 were issued in parts of unknown size on unknown dates separated from one another 

 by irregular intervals. The problem here involved was not simply one of ascer- 

 taining the dates to be assigned to the numerous new names published in these 

 works ; it was the much more important question ol the priority to be accorded to 

 many of these names in relation to other names published at about the same time by 

 other authors for the same taxa. The most important of Hiibner's works from the 

 present point of view are his Verzeichniss bekannter Schmettlinge [sic] and his Samm- 

 lung exotisclier Schmetterlinge with its companion work the Zutrdge, all of which 

 contain many new generic nanus, especially the Verzeichniss, the most important 

 work from this point of view ever published on the Lepidoptera. 



Another important work containing great numbers of new generic names, about 

 the dates of publication of which great doubts long existed and much consequent 

 confusion was caused, is Edward Doubleday's Genera of Diurnal Lepidoptera. This 

 work was published in parts, of which the first appeared in 1846, other parts appearing 

 on various dates until Doubleday's death in December 1849. Nearly a year later 

 publication was resumed under the direction of J. O. Westwood who had been 

 engaged by the publishers to carry out this task. The work was ultimately com- 

 pleted in August 1852. Almost from the beginning there was a serious lack of 

 balance between the rates at which plates and instalments of text were published. 

 Ignorance regarding the relevant rates of publication of these two portions of this 

 work gave rise to serious difficulties at the generic-name level, for there were often 



