Hymenoptera, large size of the cerebral ganglia in; classification of; sexual differences in the wings of; aculeate, relative size of the sexes of.

Hymenopteron, parasitic, with a sedentary male.

Hyomoschus aquaticus.

Hyperythra, proportion of the sexes in.

Hypogymna dispar, sexual difference of colour in.

Hypopyra, coloration of.

Ibex, male, falling on his horns; beard of the.

Ibis, white, change of colour of naked skin in, during the breeding season; scarlet, young of the.

Ibis tantalus, age of mature plumage in; breeding in immature plumage.

Ibises, decomposed feathers in; white; and black.