340 
SEXUAL SELECTION. 
Part II. 
can I find any well-marked instances of sexual dif- 
ferences such 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 legs be- 
longing to one of the anterior segments of the body, or 
to the posterior segment, are modified into prehensile 
hooks which serve to secure the female. In some 
species of lulus the tarsi of the male are furnished 
with membranous suckers for the same purpose. It is 
a much more unusual circumstance, as we shall see 
when we treat of Insects, that it is the female in 
Lithobius which is furnished with prehensile appen- 
dages at the extremity of the body for holding the 
male. 17 
17 Walckenaer et P. Gervais, ‘Hist. Nat. cles Insectes : Apteres/ 
tom. iv, 1847, p. 17, 19, G8. 
