Chapter I: Ichthyodea, characters of, 577, 579

Incongruence; in Lepidopterous families, 437;
genera, 446, 449;
species, 451;
varieties, 456;
two kinds of, 458, 502;
in Hymenoptera, 481;
in Diptera, 488;
different forms of, 503;
dependent upon action of environment, 505, 507, 508.

Inheritance; homochronic, 63, 431;
definition of cyclical, 66;
limited by sex, 68.

Insects, ancestry of, 493.

Intermaxillary gland of Axolotl, 623.

J.

Jullien, on _Lissotriton punctatus_, 591.

K.

Kant, referred to, 638, 709.

Kirby, W. F., “Synonymic Catalogue” referred to, 2, 49, 435, 449.

Kleemann, larva of _S. Ligustri_, 259.

Knaggs, Dr. H. G., seasonal dimorphism of _S. illustraria_, 4.

Kölliker, Prof., experiments with Axolotl, 564;
characters of Axolotl, 575.