458 KELLOGG AND KUWANA 



child and Hertert's is one by Ridgway,^ whose list includes 105 

 species. Ridgway's longer list of species results from regard- 

 ing as species some forms classed by Rothschild and Hertert 

 as varieties. The whole number of species of Mallophaga in 

 the collection is 43, of which 25 are new to science and are 

 here first described. Of the 18 species determined to be iden- 

 tical with previously known forms, three are represented by 

 specimens which differ so considerably from the types that 

 they must be referred to as varieties. As most of the species 

 to which the Galapagos Island forms can be referred have been 

 previously described by the senior author from birds of North 

 and Central America, the types were available for comparison 

 and no doubts as to the determinations need be entertained. 



It was hoped that the character of the parasites found on the 

 strictly Galapagos Island bird hosts might throw some light on 

 the relationships of these birds to continental genera and species, 

 but our knowledge of the distribution of the Mallophaga is yet 

 far too meager to give much value to suggestions in such direc- 

 tion and especially as we have no data at all regarding the Mal- 

 lophaga of birds from the west coast of South America, from 

 which region the Galapagos Islands doubtless received most 

 of their original fauna. Moreover, an extraordinary condition 

 referred to in the next paragraph, attending the distribution of 

 the parasites among the birds of the islands, made such an 

 attempt even less profitable than it might otherwise have been. 



When the authors first began the examination of these Mallo- 

 phaga they were startled by the unusual eccentricity of the 

 occurrence of the parasites on the various bird hosts. A species 

 of Mallophaga, obviously normal in such a strictly land bird as 

 Geos^iza would be found to occur occasionally on such strictly 

 maritime birds as terns. For example, JVtrmjis vulgatus, a 

 typical parasite of passerine birds, and heretofore found only on 

 them (twenty passerine hosts previously recorded by Kellogg) 

 occurs abundantly on Gcospiza, Nesomhmis and Camarhynchus 

 and was also found on Sterna Jtiliginosa (Clipperton Island). 

 On the other hand a common Nirnius of Sterna and Anous 

 {Nirmus gloriosus) and belonging to a group of JVh-mi, the 



^ Proc. U. S. Nat. Museum, Vol. xix, pp. 459-670, 1S96. 



