The Descent of Man

Homoptera, to be described in the next chapter,
we may feel almost sure that the stridulation
serves, as Westring also believes, to call or to
excite the female; and this is the first case
known to me in the ascending scale of the animal
kingdom of sounds emitted for this purpose.
(25. Hilgendorf, however, has lately called
attention to an analogous structure in some of
the higher crustaceans, which seems adapted to
produce sound; see 'Zoological Record,' 1869, p.
603.)
CLASS, MYRIAPODA.
In neither of the two orders in this class, the
millipedes and centipedes, can I find any wellmarked
instances of such sexual differences as
more particularly concern us. In Glomeris limbata,
however, and perhaps in some few other
species, the males differ slightly in colour from
the females; but this Glomeris is a highly variable
species. In the males of the Diplopoda, the