362 Wisconsin Academy of Sciences, Arts and Letters. 
scendents of one parent species, and that the danger attending 
conspicuous color has effaced the red in borealis; but it is diffi¬ 
cult to see, not only why the color was not equally dangerous to 
the young spider, but even how it could have been acquired be¬ 
fore maturity. The condition is one of those exceptions to a 
general rule which cannot be explained without fuller knowledge. 
Other exceptions are found in I. elegans, where the female, al¬ 
though colored differently, is quite as brilliant as the male, and 
in Bellota, where the legs of the females are enlarged and 
brightly colored. 
It is true that great vitality is found going along with the 
secondary sexual modifications, but it is also true that in many 
species of Attidse there is even greater activity with no special 
modification, while in the whole family of the Lycosidse (run¬ 
ning spiders) a high degree of bodily activity is found without 
structural or color modification. With these facts before us it 
is difficult to correlate the color development with abundant 
energy, hut even if we should grant, for the moment, that su¬ 
perior vitality accounts for color and modification we should 
still have unexplained the evident relation between the interest 
of the female and the display of peculiar decoration in the male. 
It is plain that something has guided the style of courtship in 
each species. Tor merely carrying off an overflow of energy 
one set of muscles would do as well as another, but the male is 
animated by something that makes him bring his best points to 
the attention of the female, and this not in an occasional in¬ 
stance, but so constantly and without exception that it is pos¬ 
sible, on finding a male with some 1 new appendage, to prophesy 
as to the posture that he will assume. 
Mr. Wallace, in discussing the sexual ornaments of birds, 
says that “the males, in their rivalry with each other, would 
see what plumes were most effective and each would endeavor 
to excel his enemy as far. as a voluntary exertion would enable 
him to.” This assertion that the males consciously vie with 
each other in displaying their beauty implies that the females 
are influenced by it, for surely if the males can see which plumes 
are “effective” the females can see the same thing; and if the 
