Introduction 



My study of the types of birds preserved in the national collection, 

 initiated in 194-5, was terminated in the spring of 1960. It will be readily 

 appreciated that so protracted a task, dealing with birds of all the world, 

 may have produced certain inadvertent inconsistencies of treatment, for 

 which I offer no apology. 



My understanding of what constitutes a type or cotype is precisely that 

 of the late Outrara Bangs (Bull. Mus. Comp. ZooL, vol. 70, p. 149, 1930) : 

 "When an author specifies a certain individual as his type or has one speci- 

 men from which he describes, then there is a holotype, or as it is called 

 here, following the usual custom of ornithologists, a type. On the other 

 hand, when an author describes from several specimens, and does not himself 

 designate any one as his type, all of the original specimens from the type 

 locality are of equal importance, and all are cotypes. No one of such 

 specimens can afterwards be selected by someone else, and called the type 

 (as has frequently been done by Ridgway in Birds of North and Middle 

 America) . Some authors have followed the very bad practice of designating 

 a male and a female type, in which case both must be listed as cotypes." 



Stability of nomenclature is often attained by choice of a lectotype from a 

 multiple series; this is especially true when the original material has been 

 demonstrated to be composite in nature. I have not, however, granted 

 recognition to a lectotype except in cases in which some reviser has shown 

 its necessity and has, so far as it has been possible, again brought together 

 all the first describer's material and has selected that one of the original 

 series that (1) best agrees with the description and (2) preferably comes 

 from a locality which, in the light of modem knowledge of range, will best 

 serve the cause of stability. If one of von Tschudi's equivalent cotypes 

 is in Neuchatel, a second in London, and a third in Washington, the fact 

 that such an authority as Hartert has stated that the type is in Neuchatel 

 does not stultify the claims of the cotypical specimens in London and Wash- 

 ington, sent away from Neuchatel at a time when the importance of types in 

 general was barely, or not at all, understood. If, however, someone were to 

 show that the three supposed cotypes represent two distinct forms and were 

 to restrict the use of von Tschudi's name to the one exemplified by the 

 Washington specimen, the London cotype, exactly like it, is no less a cotype 

 for the now restricted name; if, moreover, the Washington bird should 

 become lost to science, the one in London must then represent the only 

 possible type. 



vn 



