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Show 346 found one female as bright as the dullest male. It is my opinion that the same remarks apply to variety tephrocotis." The above statements of Captain Bendire and Lieutenant Bacon are made in reference to some very positive remarks by Mr. Robert Ridg-way, in his recent very elaborate monograph of the genus Leucosticte^ in respect to sexual variation among the different forms of this group. Mr. Kidgway says, " The American species of this genus fall into two distinct groups, according as the sexes do or do not differ in appearance. * In L. tephrocotis, in all its forms, there is not the slightest sexual difference ; but, in L. atrata and L. australis, the distinction is very marked.* * Under the head of L. tephrocotis var. littoralis, Mr. Bidgway further says, " In regard to the two sexes, as compared to one another, there is the same absolute similarity in appearance and sizei that exists in grtiei-nucha and tephrocotis, many females i being more brightly colored and some larger than some males. The apparently larger average of the dimensions of the [ seven] femalefsj indicated in the above measurements is no doubt due to the small number of specimens of the sex examined.^ Mr. Bidgway's tables seem to indicate that the sex was known in only a small proportion of his specimens, namely, in fourteen ( seven males and • seven females) out of forty- eight in variety Uttoralis, and in about one-third in variety tephrocotis. As already stated, Captain Bendire's specimens, in which the sex was carefully determined by dissection, show - a very considerable constant sexual difference in coloration, and, as will be presently shown, also in size. Through some unfortunate inadvertence, an important error has crept into Mr. Bidgway's table of comparative measurements given ou page • 60 ( I. c.); the measurements of the two sexes of L. tephrocotis being given - as, male, wing, 4.21; tail, 3.12; female, wing, 4.16; tail, 3.12; thus apparently sustaining Mr. Bidgway's generalization in respect to the absence of difference in size in the two sexes of this form. In examining Captain Bendire's specimens, however, I was struck with the apparently smaller size of the females; and, on referring to the measurements recorded on his labels, this apparent difference proved to be real. I then turned to Mr. Bidgway's table of the measurements of L% tephrocotis^ - and, carefully computing the averages given by Mr. Bidgway, I met with vquite different results, the thirty- four females giving an average length of wing of 4.05, and of tail of 2.97, against the 4.16 and 3.12 given by Mr. Bidgway, and of course giving a considerably smaller average than for the males, namely, 4.05 against 4.21 for the wing, and 2.97 against 3.12 for the tail. The averages given in the same connection by Mr. Bidgway for the two sexes of L. littoralis ( seven males and seven females) are borne oat by the table of measurements on which they are based, and seem to indicate that there is no sexual variation in size in this form. Through the kindness of Captain Bendire, I have before me measurements ( sent to me by my special request) of forty- two males and twenty- six females of L. littoralis, in which the wing averages respectively 4.23 for the males and 4.05 for the females. In addition to these, seven males and six females, which he had previously sent me, gave 4.19 for the length of the wing in the male and 4.02 for the same in the female; thus showing that not only in coloration but also in size there is a well-marked sexual variation in this form as well as in tephrocotis, about the * " Monograph of the genus Leucosticte," etc., Bull. U. S. Geo'. og. and Geograph. Survey of the Territories. No. 2, second series, p. CO, May, 1370. t Not italicized in the original. t Loc. cit., p. 75. |
