Occupations, sometimes a cause of diminished stature; effect of, upon the proportions of the body.
Ocelli, absence of, in female Mutilidae.
Ocelli of birds, formation and variability of the.
Ocelot, sexual differences in the colouring of the.
Ocyhaps lophotes.
Odonata.
Odonestis potatoria, sexual difference of colour in.
Odour, correlation of, with colour of skin; of moths; emitted by snakes in the breeding season; of mammals.
Oecanthus nivalis, difference of colour in the sexes of.
Oecanthus pellucidus.