1 86 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



longed. Remainder of head, /. e., lower sides of face, the auricular region 

 and lower half of the loral region white. 

 Neck : Wholly white. 



Back : Mantle pearl grey ; rump and upper tail coverts pale pearl grey. 

 Wing: In general color pearl grey, with a-decided white line along the 

 carpal joint. The first primary dark grey on outer web, heavily frosted 

 with pearl grey ; a third of the inner web dark grey to tip, frosted like the 

 outer web. Remainder of inner web, abruptly whiter, the line of division 

 between the two colors absolutely straight for the entire length. The white 

 on the inner webs of the rest of the primaries cut- 

 ting into the grey of the inner web toward the tip 

 in well-defined wedges. The extreme edge of all 

 the inner webs of the primaries at their ends, nar- 

 rowly margined with white. Shafts of all the pri- 

 maries ivory white. The secondaries are edged 

 with white, but not conspicuously. 

 Sterna maxima. Profile Tail : Pearly white. Under parts : Pure white, 

 of head. Female. 4770 Bill : Rcddish Orange. Tarsi: Black. Feet: Black. 



P. U. O. C. Winter plum- t • t^ 1 i, 1 u ^ 



\ . Ins: Dark hazel brown. 



age. About \\ natural size. _,, . , , . ^. ^ .... 



The female differs from the male m havmg on 

 the average a stouter bill and shorter streamers to the tail. Both sexes 

 begin to have a few white feathers show on forehead and crown early 

 in the breeding season. 



Adults in autumn and winter (Female, 4770, P. U. O. C, Gulf coast 

 of Florida, 15 December, 1879, W. E. D. S.), are similar to breeding 

 birds, but have the forehead and loral region wholly white, the crown 

 mottled with black feathers, and the long occipital feathers edged with 

 white in a varying degree. Bill pale orange. There is generally a 

 crescentic black area just in front of the eye. Immature young birds of 

 the year have whiter crowns and a greater admixture of white in the black 

 feathers of the occipital region. There is also a varying amount of grey 

 or brownish grey on the wing coverts, the secondaries, and toward the 

 tips of the rectrices. 



Young birds fully grown have dusky brown streaks on the lores, the 

 forehead and fore part of the crown ; the mantle is darker than in adults, 

 more or less striated and marked with deeper grey, dusky and buffy ; this 

 extends to the rump and upper tail coverts. The primaries are iron-grey, 



