AVIFAUNA OF LAYSAN, ETC. 



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TEE GENUS OHASIEMPIS. 1 



Tins gdius was established by Cabanis in the 'Arcliiv fur Naturgeschichte,' 1847, p. 207. 



The members of this genus are true Flycatchers, having broad and soft bills, and 

 the gape beset with long and strong bristles. The tarsus is long and slender. The first 

 primary is about half as long as the second, the second about one quarter of an inch 

 shorter than the third; the fourth, fifth, and sixth are equal and longest. The tail is about 

 as long as the wing, and the rectrices are pointed. 



The sexes are similar, but the plumage of the young differs remarkably from that of the 



adult bird. 



The differences between the old and young birds have led many authors to describe them 

 under different names, so that as many as five or six species were believed to exist, while 

 some other distinguished ornithologists referred all to one species. I have already pointed 

 out that three species are found on three different islands (Bull. B. O. C. 1893, vol. i. p. lyi). 

 No species of the genus is known to occur out of the Hawaiian Islands, so we may fairly 

 regard it as entirely peculiar to this Group. 



Sbarpe (Cat. B. iv. p. 232, 1879) includes in the genus Chasiempis the Monarcha dimir 

 diata, Hartl. & Finsch, from Rarotonga, Samoa (P. Z. S. 1871, p. 28), but with our present 

 knowledge of the genus Chasiempis he would certainly alter his opinion. The Monarcha 

 dimidiata of Hartl. & Finsch has the peculiar short scaly-looking feathers on the forehead 

 which occur in several genera of Flycatchers distinctly developed (though not so much as 

 in other genera), while nothing of the sort is seen in Chasiempis. The sexes in Monarcha 

 dimidiata, H. & P., are of a totally different colour, while they arc alike in Chasiempis. 

 The bill 'is stronger and higher in Monarcha dimidiata, II. & P., than in Chasiempis ; 

 the tail-feathers in the former seem to be rounded, while they are distinctly pointed in 

 the latter. Through the kindness of Professor A. Newton I was enabled to compare 

 the two specimens in the Cambridge Museum, which also served Dr. Sharpe for his 

 descriptions in the ' Catalogue of Birds.' 



The nest is open and the eggs are spotted. 



Not Cliasiempsis, as erroneously spelt by Hartlaub, Gray, and Dole. 



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