No. 604] SHORTER ARTICLES AND DISCUSSIONS 



255 



by barred (Plymouth Eock) and black, or near-black, chickens 

 living under the same conditions is also mentioned. In this 

 paper photographs show the black fowls looming up against 

 natural backgrounds much more distinctly than do the barred. 

 This is accepted as "objective and unbiased evidence regarding 

 the relative conspicuousness of the two types of plumage 

 pattern." It follows naturally, since the extensive record shows 

 little difference in the rate of elimination of the two sorts of 

 birds, that "the relative inconspicuousness of the barred color- 

 pattern afforded its possessors no great or striking protection 

 against elimination by natural enemies." But photographs 

 serve as accurate measures of the conspicuousness of the fowls in 

 the eyes of color-blind enemies only. Therefore, if rats and pre- 

 daceous birds are not color-blind, and there is perfectly good 

 reason for supposing that creatures lower in organization than 

 either have color vision, it is not at all certain that the elimina- 

 tion in the two cases does not correspond fairly well with the 

 actual difference in conspicuousness of the two types. 



Kellogg and BellV interesting "Studies of Variation in In- 

 sects" deals with 24 species. In 23 of them, including the lady- 

 beetle, Hippodamia, to which Dr. Pearl refers, the authors show 

 that there is much variation in individuals which have success- 

 fully run the gauntlet of natural selection. But since they 

 have no knowledge whatever of the variation in the original 

 populations, of which they have studied survivors only, these 

 tlieir results show nothing regarding the extent, or even the oc- 

 currence, of selective elimination. 



In the honey bee alone duplicate studies were made of the 

 variation of certain structures in individuals which were about 

 to hatch, and in others, apparently from the same hive, after 

 exposure to the vicissitudes of an active life. Among 200 drones 

 in the first group the veins of the fore wings in 11 were im- 

 perfectly developed, and as a result normal flight became difficult 

 or impossible. The variation in others of the first series seems 

 essentially the same as that observed in the 300 members of the 

 second, among which none of the defective individuals were 

 found. But if these facts prove anything, it seems to be that 

 selective elimination does occur when unfavorable variations 

 affect the normal functioning of an organ. Suggestion is en- 

 tirely lacking that the mechanical efficiency of the wing is im- 

 paired by the other variations noted, and it can scarcely be con- 

 5 Kellogg, V. L., and Bell, E. G., 1904, "Studies of Variation in Insects," 

 Proc. Washington Acad, of Sciences, Vol. 6, pp. 203-332. 



