i. 311;

on the attraction of the males of _Lasiocampa quercus_ and _Saturnia carpini_ by the female, i. 312; on the proportion of the sexes in the Lepidoptera, i. 312; on the ticking of _Anobium tessellatum_, i. 385; on the structure of _Ageronia feronia_, i. 387; on white butterflies alighting upon paper, i. 400.

DOUGLAS, J. W., on the sexual differences of the _Hemiptera_, i. 349; on the colours of British _Homoptera_, i. 352.

DOWN, of birds, ii. 80.

_Draco_, gular appendages of, ii. 33.

DRAGONET, Gemmeous, ii. 7.

DRAGON-FLIES, caudal appendages of male, i. 344; relative size of the sexes of, i. 347; difference in the sexes of, i. 361; want of pugnacity by the male, i. 364.

DRAKE, breeding plumage of the, ii. 84.

DREAMS, i. 46; a possible source of the belief in spiritual agencies, i. 66.

DRILL, sexual difference of colour in the, ii. 291.

_Dromoeus irroratus_, ii. 204.

_Dromolaea_, Saharan species of, ii. 172.

DRONGO shrike, ii. 179.

DRONGOS, racket-shaped feathers in the tails of, ii. 73, 83.

DRYNESS, of climate, supposed influence of, on the colour of the skin, i. 242.

_Dryopithecus_, i. 199.

DUCK, harlequin, age of mature plumage in the, ii. 213; breeding in immature plumage, ii. 214.

DUCK, long-tailed, preference of male, for certain females, ii. 122.

DUCK, pintail, pairing with a wigeon, ii. 114.

DUCK, voice of the, ii. 60; pairing with a shield-drake, ii. 114; immature plumage of the, ii. 188.

DUCK, wild, sexual differences in the, i. 268; speculum and male characters of, i. 291; pairing with a pintail drake, ii. 115.

DUCKS, dogs and cats recognised by, ii. 110; wild, becoming polygamous under partial domestication, i. 270.

DUGONG, tusks of, ii. 242; nakedness of, i. 148.

DUJARDIN, on the relative size of the cerebral ganglia in insects, i. 145.

DUNCAN, Dr., on the fertility of early marriages, i. 174.

DUPONT, M., on the occurrence of the supra-condyloid foramen in the humerus of man, i. 29.

DURAND, J. P., on causes of variation, i. 113.

DUREAU de la Malle, on the songs of birds, i. 55; on the acquisition of an air by blackbirds, ii. 55.

DUTCH, retention of their colour by the, in South Africa, i. 242.

DUTY, sense of, i. 70.

DUVAUCEL, female _Hylobates_ washing her young, i. 40.

DYAKS, pride of, in mere homicide, i. 94.

_Dynastes_, large size of males of, i. 347.

DYNASTINI, stridulation of, i. 381.

_Dytiscus_, dimorphism of females of, i. 343; grooved elytra of the female, i. 343.

E.

EAGLE, young _Cercopithecus_ rescued from, by the troop, i. 75.

EAGLE, white-headed, breeding in immature plumage, ii. 214.

EAGLES, golden, new mates found by, ii. 105.

EAR, motion of the, i. 20; external shell of the, useless in man, i. 21; rudimentary point of the, in man, i. 22.

EARS, piercing and ornamentation of the, ii. 341.

_Echidna_, i. 201.

_Echini_, bright colours of some, i. 322.

ECHINODERMATA, absence of secondary sexual characters in, i. 321.

ECKER, figure of the human embryo, i. 15; on sexual differences in the pelvis in man, ii. 317; on the presence of a sagittal crest in Australians, ii. 319.

EDENTATA, former wide range of, in America, i. 219; absence of secondary sexual characters in, i. 268.

_Edolius_, racket-shaped feathers in, ii. 73.

EDWARDS, Mr., on the proportion of the sexes in North American species of _Papilio_, i. 309.

EGERTON, Sir P., on the use of the antlers of deer, ii. 252; on the pairing of red deer, ii. 269; on the bellowing of stags, ii. 275.

EGGS, hatched by male fishes, ii. 20.

EGRET, Indian, sexes and young of, ii. 217.

EGRETS, breeding plumage of, ii. 82; white, ii. 228.

EHRENBERG, on the mane of the male Hamadryas baboon, ii. 267.

EKSTROEM, M., on _Harelda glacialis_, ii. 122.

_Elachista rufocinerea_, habits of male, i. 311.

ELAND, development of the horns of the, i. 289.

ELANDS, sexual differences of colour in, ii. 288.

_Elaphomyia_, sexual differences in, i. 349.

_Elaphrus uliginosus_, stridulation of, i. 379.

_Elaps_, ii. 31.

ELATERIDAE, proportions of the sexes in, i. 313.

ELATERS, luminous, i. 345.

ELEPHANT, i. 200; nakedness of the, i. 148; rate of increase of the, i. 135; Indian, polygamous habits of the, i. 267; pugnacity of the male, ii. 240; tusks of, ii. 242, 243, 248, 249, 258; Indian, mode of fighting, of the, ii. 257; male, odour emitted by the, ii. 279; attacking white or grey horses, ii. 295.

ELEVATION of abode, modifying influence of, i. 120.

ELIMINATION of inferior individuals, i. 172.

ELK, ii, 249; winter change of the, ii. 299.

ELK, Irish, horns of the, ii. 259.

ELLICE Islands, beards of the natives, ii. 322, 349.

ELLIOT, R., on the numerical proportion of the sexes in young rats,