RELATING TO SECONDARY SEXUAL CHARACTERS. 57 



one, perhaps too greatly, against accepting a special (even an implied 

 intentional) exhibition of the specially ornamented parts. On the 

 other hand, if it be conceded that the conspicuousness of the male is 

 an element in the reaction, the very special adornments visible from 

 the front might be supposed to enhance the effect produced in the 

 female. Similar displays of special ornamentation in the male have 

 been described both for birds and insects, but here, too, the question 

 has been raised as to whether such exhibitions are more than an 

 accidental accompaniment of the posturing of the male, for the same 

 kind of behavior is known to occur in other cases where the male is 

 unornamented and resembles the female. Had such a male special 

 ornamentation it would no doubt appear to us that his behavior was 

 "calculated" to display his ornaments. 



Dr. and Mrs. Peckham point out that their observations are entirely 

 inconsistent with Wallace's interpretation of the origin of secondary 

 sexual characters. They find no evidence in favor of his view that the 

 male possesses greater "vital activity." On the contrary, the female 

 is the more active and pugnacious of the two. They also object to 

 Wallace's statement of a total absence of any evidence that the female 

 notices the display of the male. In spiders the females "observe" the 

 males with close attention during their courtship. They point out also 

 that, in spiders at least, as the female gradually becomes adult, a male 

 if preferred will have a chance of mating with several females, "and 

 as the mating season lasts for two or three weeks the more brilliant 

 males may easily be selected again and again." In regard to Wallace's 

 argument as to the distribution of accessory plumes in humming birds, 

 the Peckhams point out that — 



"The pectoral muscles reach their highest development in the humming- 

 birds, the diurnal birds of prey, and the swallows, and wo may, therefore, 

 fairly use these groups to test Mr. Wallace's explanation of breast plumes. In 

 the swallows and birds of prey we find no such appendages, in spite of their 

 further claim to them, on the ground of great vigor and activity. As to the 

 humming-birds, we find in the genus Aglceactis six species with more or less 

 developed breast-plumes, which are also found in nine other species, scattered 

 through different genera — in all, only fifteen species out of four hundred and 

 twenty-six; while we find in fifty-six species the lengthened and modified tail- 

 feathers, which, according to Mr. Wallace's view, should be peculiar to the 

 Gallinacese. 



"Again, there are elongated feathers from the throat or from the side of the 

 neck in thirty-five species, while seventeen have crests from the top of the 

 head, and seventeen, downy puffs from the tarsi." * 



From this brief survey of the family we see that, contrary to what 

 we should expect from Mr. Wallace's theory, although the breast 

 muscles are the seat of the highest activity, breast plumes are the least 

 frequent of all the forms of ornamental plumage. 



1 Loddigesia mirabilis has the tail about three times as long as the body. Similar modifiw itiom 

 are found in the genera Sappho, Cynanthus, Lesbia, Stegnura, Di.icura. Oo wW i 'a , ct al. 



