ORNITHOLOGICAL EXPLORATIONS. 63 



bird glaucescens "Licht.," which was uot the glaucescens of Lichten- 

 steiu (?)* Lichtenstein's name is only a museum name which would, 

 take no precedence over Bruch's glaucescens of 1853 if no description 

 had been published prior to that year. In that case the species would 

 have to stand as glaucopterus Bruch (ex Kittlitz in MSS.), 1853. 



Fortunately enough we have a much earlier description of the type 

 of the Berlin Museum, and that a description which is much superior 

 to any of the descriptions or diagnoses of Bruch or Bonaparte. 



•3?his description is found in Naumaun's Naturgeschichte der Vogel 

 Deutschlands, X, p. 351 (1840), and as this original and excellent char- 

 acteristic of L. glaucescens has been entirely overlooked by all authors 

 up to the present day, I propose to give a full translation of Naumann's 

 remarks. He says : 



"A much nearer ally [to L. glaucus] with much greater similarity [to 

 it than to L. leucopterus] is a species of the same size, the L. glaucescens, of 

 the Berlin Museum, from i!>forth America, where it seems to represent 

 our glaucus. Although the size and shape (of bill and feet also) of both 

 are very similar, still L. glaucescens in the adult plumage is easily dis- 

 tinguishable by the different color and pattern of the primaries, these 

 being uniform bluish ashy gray, with large snow-white tips, the border 

 of the two colors being very distinctly marked across the feathers; the 

 white tips consequently are much more conspicuous than in glaucus, in 

 which they pass gradually into the gray color, showing in fact the same 

 pattern as in L. marinus, only that in the latter those parts are black 

 which in L. glaucescens are but bluish ash. Besides, the mantle of the old 

 L. glaucescens is of a somewhat more saturated gull-blue (similar to the 

 color of L. argentatus), while in L. glaucus it is much lighter or more 

 whitish. The young L. glaucescens is likewise distinguishable by the 

 darker brownish gray of the primaries, the white tips of which, however, 

 are less distinctly separated from the dark color, although much more 

 so than in the young of L. glaucus; the spots on the mantle are larger 

 and somewhat darker though more blended into the light edges of the 

 feathers, the whole region thus being more broadly but at the same time 

 more indefinitely blotched." To this he adds in a foot-note: ''I am 

 ignorant of any minute descrii:)tion or figure of this beautiful large 

 species which in coloration is intermediate between L. marinus and 

 L. glauctis. It belongs to the more recent discoveries." 



Thus Larus glaucescens is "hunted down" to the original description! 



* Bracb's glaucescens of 1855 ia the same as Lichtenstein's, however. 



