Ophideres fullonica, [311]

Opomyzidae, [504]

Opostega, [429]

Orange-tip, [357]—see also Euchloe

Orectochilus, [216]

Oreta hyalodisca, [400]

Origin of parasitic bees, [32]

Orneodidae, [340], [371], [426]

Ornithoptera, [360];

O. brookiana, [362];