THE BIRDS OF CLIPPERTON AND COCOS ISLANDS 5O9 



separating the first syllable from the others, the variation being noticed 

 especially when the birds were flying. When sitting on the ground 

 they were generally quiet — in striking contrast to their noisiness while 

 on the rock. When a flock rose from the ground, even as a result of 

 disturbance, the members seldom made any sound. 



One egg was obtained. In color, shape and size it is indistinguish- 

 able from those of Sterna fuliginosa. Color, creamy- white with dis- 

 tinct blotches and spots of dark brown mostly about the larger end, 

 amongst these spots similar, very pale, almost obsolete markings. Size 

 52 X 38 mm. 



We found this species common on Cocos Island in July. 



MICRANOUS DIAMESUS Heller and Snodgrass. 



Micrattotis diaviestis Heller and Snodgrass, The Condor, iii, No. 3, May, 

 1901, p. 76 (Cocos and Clipperton Islands). 



Range. — Cocos and Clipperton Islands, eastern tropical Pacific. 



Adult Male. — Type of species. Cat. No. 5079, Stanford Univer- 

 sity Museum, from Cocos Island, July i, 1S99. Forehead and top of 

 head almost pure white, back part of head and nape with a plumbeous 

 tinge. Lower part of neck plumbeous, darkening into dark plumbeous 

 on the shovilders and then into brown on the mantle. Rest of upper 

 parts, except upper tail coverts and tail, dark dusky-brown ; outer 

 webs of outer primaries sooty-brown, almost black. Upper tail coverts 

 and tail dark plumbeous-gray. Under parts dusky-brown, darkest on 

 lower breast and on belly. Lower tail coverts somewhat lighter 

 plumbeous-brown. Tail below same color as above. Lores and 

 superciliary line black, a small white spot in the latter above the pos- 

 terior part of the eye. Lower two thirds of lower eyelid white. 

 Cheeks deep, dark plumbeous, the pale color of back of head scarcely 

 extending upon the lateral joarts. 



Immature Male. — Top of head pure white, with a few brown 

 feathers posteriorly. Outer webs of outer primaries blackish-brown, 

 that of the first almost black. Lores, superciliary line and cheeks 

 dusky brown. All other parts sooty -brown with no dusky tinge ex- 

 cept on the lower part of throat. 



This species is intermediate between M. leticocapilhis Gould of the 

 Caribbean Sea, Atlantic and Indian Oceans and the western Pacific, 

 and M. ha-waiiensis Rothschild of the Hawaiian Islands in both color 

 of plumage and size of bill. It differs from M. hazvaiietisis in being 

 darker on the shoulders, on lower part and sides of neck, and on sides 

 of head, and in having a longer and thicker bill and a longer middle 



