178 Evolution and Adaptation 
from each other in color, the males are often of a darker shade 
than the females. “In some species, however, the difference 
is conspicuous ; thus the female of Sparassus smaragdulus is 
dullish green, whilst the adult male has the abdomen of a fine 
yellow with three longitudinal stripes of rich red.” Darwin 
believes that sexual selection must take place in this group, 
because Canestrini has observed that the males fight for the 
possession of the females. He has also stated that the 
males pay court to the female, and that she rejects some of 
the males who court her, and sometimes devours them, until 
finally one is chosen. Darwin believed, -on this evidence, 
that the difference in color of the sexes had been acquired 
by sexual selection, “though we have here not the best kind 
of evidence—the display by the male of his ornaments.” 
This evidence has, however, now been supplied through 
the interesting observations of Mr. and Mrs. Peckham. 
These accurate observers have studied the courtship of the 
male, and observed that during the process, he twists and 
turns his body in such a way as to show to best advantage 
his colors to the female. From their account this certainly 
appears to be the result of his movements, but whether this 
is really the case, and whether the female makes any choice 
amongst her suitors, according to whether they are more or 
less brilliantly marked, we are absolutely ignorant. The fol- 
lowing account given by Darwin should not pass unnoticed :— 
“The male is generally much smaller than the female, 
sometimes to an extraordinary degree, and he is forced to be 
extremely cautious in making his advances, as the female 
often carries her coyness to a dangerous pitch. De Geer 
saw a male that ‘in the midst of his preparatory caresses 
was seized by the object of his attentions, enveloped by her 
in a web and then devoured, a sight which, as he adds, filled 
him with horror and indignation.’ The Rev. O. P. Cam- 
bridge accounts in the following manner for the extreme 
smallness of the male in the genus Nephila. ‘M. Vinson 
