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Show • SEXUAL, INDIVIDUAL, AND GEOGRAPHICAL VARIATION IN LEU-COSTIOTE TEPHROCOTIS. BY J. A. ALLEN. Some months since, my attention was called by Capt. Charles Bendire, U. S. A., to the fact of the existence of a well- marked difference in color between the sexes of two varieties of Leucosticte tephrocotis, namely, littoralis and tephrocotis. Under date of January 28, 1876, Captain Bendire wrote me, " There is a good deal of difference between the sexes of both varieties; so much that they can in almost every case be separated before dissection. The brown on the breasts of the females is much duller than that of the males." This statement, he added, was based on a series of seventy specimens of variety littoralis and on a series of about a dozen specimens of variety tephrocotis. Under date of April 18, Captain Bendire wrote me further on the subject, he in the mean time having sent me two lots of specimens, about two dozen examples in all, which seemed to fully confirm his statements. In the later account, in speaking of a series of eighty- five specimens of variety littoralis, of which the sex of each had been determined by careful dissection, he says there was not a single female in the whole lot that was as bright as the palest- tinted males. He says further, " I have examined over two hundred skins of variety littoralis and about thirty of variety tephrocotis. I find a constant difference, and have never yet obtained a female which I could not readily distinguish from a male before skinning; but, nevertheless, every specimen was dissected, and the sex not guessed at." With this letter was forwarded to me by Captain Bendire a series of thirteen skins of variety littoralis and three of variety tephrocotis, which were selected impartially by himself and Lieut. George B. Bacon, to show the extreme ranges of variation in color in the two sexes of each variety. The series of variety littoralis was taken from a lot of eighty- two skins, and is stated to embrace two of the brightest females and several of the dullest males of the whole lot. Separating the series by color, without reference to the labels, I found, on looking at the labels, that I had placed all the females in one series and all the males in the other. In the case of only one specimen was there any reason for hesitancy in making the separation; but this even, 1 found on reference to the label, I had placed in its proper series. The general aspect of the two series I found was quite different, noticeably so at a considerable distance, through the much paler tints of the females. " Several of the skins", adds Captain Bendire, " are poorly prepared; but they will answer every purpose for description, and I repeat my statement that they represent the brightest females and dullest males of the whole lot? Lieutenant Bacon, who assisted in making the selection, says ( writing at the same time) that the series sent to me was made up with great care, so as to show the dullest and brightest of each sex. " I have prepared", Lieutenant Bacon adds, " some eighty skins of variety littoralis,& nd have found no difficulty in distinguishing the sexes before skinning. I have not |
