286 



ORNITHOLOGICAL EXPLORATIONS. 



especially on the anterior part of the back, of which black clouding the 

 two supposed ocularis have not the slightest trace. A further comparison 

 convinces us that in the latter the black cap is confined to the posterior 

 half of the head and part of the nape, while in the females of higens it 

 occupies also the upper neck. The black of the upper tail-coverts in 

 the latter is likewise not only more extended, but also more intensive 

 in color. Considering the great variation in these birds in the amount 

 of the white on the wing, it would be rather useless to undertake a 

 detailed description of the differences. But it may be stated, how- 

 ever, that, on the whole, the two ocularis seem to have the white less 

 developed than is the case in those birds with which they have been 

 compared. 



The dimensions, as given in the tables below, show that our two birds 

 in question are somewhat intermediate in size between the males and 

 females of lugeiis, as represented by the average measurements on page 

 291, the tail being perhaps a little longer in proportion to the wing, and 

 it is noteworthy that we find the same relations between the meas- 

 urements of the two forms as given by Taczanowski (Bull. Soc. Zool. 

 France, 1882, p. 389). It may finally be stated that the bills of the two 

 ocularis are somewhat smaller-, being on an average 1"'"' shorter than in 

 the males, and 0.5 """ shorter than in the females of the true lugens. 



These differences, together with the unusual late api)earance of the 

 bird, make me believe that I am justified in identifying No. 88988 as be- 

 longing to ocularis, and not to lugens, and it is altogether probable that 

 the differences pointed out above are really diagnostic for separating 

 examples of the former from females of the latter species.* 



Dimensions of the specimen, collected. 



* A straggler was shot at La Paz, in Lower California, by Mr. Bclding, on the 9th of 

 January, 1882, and identitied by Mr. Ridgway (Pr. U. S. Nat. Mus., IV, p. 414) as M. ocu- 

 laris, a determination which, in my opinion, is nndoubtedly correct. I have compared 

 it with fall specimens from Kamtschatka and liud it differing in the same manner as 

 above, viz, the back has a much more decided wash of brownish and the bill is ab- 

 solutely smaller. 



