INSECTS, regeneration of lost parts in. -agency of, in fecundation of larkspurs. -effect of changed conditions upon. -sterile neuter. -monstrosities in.

INSTINCTS, defective, of silkworms.

INTERBREEDING, close, ill effects of.

INTERCROSSING, of species, as a cause of variation. -natural, of plants. -of species of Canidae and breeds of dogs. -of domestic and wild cats. -of breeds of pigs. -of cattle. -of varieties of cabbage. -of peas. -of varieties of orange. -of species of strawberries. -of Cucurbitae. -of flowering plants. -of pansies.

INTERDIGITAL pits, in goats.

INTERMARRIAGES, close.

INTESTINES, elongation of, in pigs. -relative measurement of parts of, in goats. -effects of changed diet on.

Ipomoea purpurea.

IRELAND, remains of Bos frontosus and longifrons found in.

IRIS, hereditary absence of the. -hereditary peculiarities of colour of the. -variation of.