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 Leitcosticte, in 

 respect to sexual variation among the difterent forms of this group. Mr. 

 Ridgway says, "The American species of this genus fall into two dis- 

 tinct 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 ditt'er- 

 ence ; but, in L. atrata and L. cnisiralis, the distinction is very marked.'' * 

 Under the head of X. .tephrocotis var. littoralis, Mr. liidgway further 

 says, " In regard to the two sexes, as compared to one another, there is 

 the same ahsohite similarity in appearance and size\ that exists in grisei- 

 7iucli a nud tephrocotis^ many females \\)Q\\ig more brightly colored and 

 some larger than some males. The apparently larger average of the 

 dimensions of the [seven] female[sj indicated in the above measurements 

 is no doubt due to the small number of specimens of the sex examined.''| 



Mr. Ridgway'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 littoraliSj and in about one- 

 third in variety tephrocotis. As already stated. Captain Bendire's speci- 

 mens, in which tbe 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. Ridgway's table of comparative measurements given on page 

 60 [1. c); the measurements of the two sexes ofL. tephrocotis being given 

 as, male, wing, 4.21 ; tail, 3.12; female, wing, 4.16; tail, 3.12 ; thus ap- 

 parently sustaining Mr. Ridgway's generalization in respect to the 

 absence of difference in size in the two sexes of this form. In examin- 

 ing Captain Bendire's specimens, howev^er, I was struck with the appar- 

 ently 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. Ridgway's table of the measurements ofL. tephrocotis, 

 and, carefully computing the averages given by Mr. Ridgway, I met with 

 quite 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. Ridgway, 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. Ridgway for the 

 t^o sexes of L. littoralis (seven males and seven females) are borne out 

 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 measure- 

 ments (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 



*"MoDograph of the geuos Leucosticte" etc., Bull. U. S. Geo'og. and Geograpb. Sur- 

 vey of the Territories, No. 2, second series, p. 60, May, 1375. 

 tNot italicized in the original. 

 1: Loc. cit., p. 75. 



