Orsodacna atra, difference of colour in the sexes of.
Orsodacna ruficollis.
Orthoptera, metamorphosis of; stridulating apparatus of; colours of;
rudimentary stridulating organs in female; stridulation of the, and
Homoptera, discussed.
Ortygornis gularis, pugnacity of the male.
Oryctes, stridulation of; sexual differences in the stridulant organs
of.
Oryx leucoryx, use of the horns of.
Osphranter rufus, sexual difference in the colour of.
Ostrich, African, sexes and incubation of the.
Ostriches, stripes of young.
Otaria jubata, mane of the male.
Otaria nigrescens, difference in the coloration of the sexes of.
Otis bengalensis, love-antics of the male.
Otis tarda, throat-pouch of the male; polygamous.
Ouzel, ring-, colours and nidification of the.
Ouzel, water-, singing in the autumn; colours and nidification of the.
Ovibos moschatus, horns of.
Ovipositor of insects.
Ovis cycloceros, mode of fighting of.
Ovule of man.
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