The Descent of Man

ordinary coloration of the genus to which the
species belong; but Mr. Blackwall thinks that,
as a general rule, it is the male; and Canestrini
(19. This author has recently published a valuable
essay on the 'Caratteri sessuali secondarii
degli Arachnidi,' in the 'Atti della Soc. Veneto-Trentina
di Sc. Nat. Padova,' vol. i. Fasc. 3,
1873.) remarks that in certain genera the males
can be specifically distinguished with ease, but
the females with great difficulty. I am informed
by Mr. Blackwall that the sexes whilst young
usually resemble each other; and both often
undergo great changes in colour during their
successive moults, before arriving at maturity.
In other cases the male alone appears to change
colour. Thus the male of the above brightcoloured
Sparassus at first resembles the female,
and acquires his peculiar tints only when
nearly adult. Spiders are possessed of acute
senses, and exhibit much intelligence; as is well
known, the females often shew the strongest
affection for their eggs, which they carry about