INDEX. 
IX. 
Hogs, imported by Columbus into 
America, 52. 
Holmes, Dr. Oliver W. : on 
variation, 3-4 ; on influence of 
external conditions on coloura 
tion of insects, 402. 
Homology, Law of: 336-7. 
Homoptera : protective secretion 
of, 166. 
Hooker, Sir Joseph (quoted by 
Wallace) : on usual abortiveness 
of attempts to naturalise plants, 
in; on geographical distribu 
tion of plants, 530. 
Horse-breeding : types to be aimed 
at in, 143-4. 
Horses: isolation in breeding, 381; 
influence of external conditions 
on, 397 > an illustration of or 
ganic evolution, 552—v. also 
Mares. 
Race, English : evolution 
of, 335- 
Teeth of: an illustration of 
organic evolution, 552-3. 
Trotting, American : 335, 
433- 
Wild : rough games of, 100; 
extinction of, in South America, 
318- 
Horse-fly, English, in New Zea 
land : destruction of, by native 
fly, 105. 
House, Prof. E. H.: on hereditary 
athleticism, 434. 
Huber, Pierre : on animal in 
stinct, 228, 278. 
Hudson, W. H.: on destruction 
following a great “ wave of life ” 
among imported animals, etc., 
53, 54, 2 97 5 on parental devotion 
in deer, 83 ; on co-operation and 
strife for mastery amongst mam 
mals, 99-102; on difference be 
tween flocks of birds and herds 
of cattle, 99 ; on persecution of 
wounded individual by herd, 
100- 1 ; on rescuing instinct, 
101- 2 ; on protective effluvium 
of skunk, 210, 211-2 ; example of 
instinct in mice and absence of 
instinct in all cats but one, 231 ; 
on habits of bisache, 253, 
254. 
Humboldt, Alex. v. (quoted by 
Darwin) : on influence of exter 
nal conditions on man, 398. 
Hutchinson, Rev. H. N. : on 
Cuvier’s discovery of extinct 
types, 314. 
Huxley, Prof. Thos. H. : on 
variation, 10, 35 ; on chance in 
Natural Selection, 26-7, 29-30, 
70-1 ; on rate of increase of 
plants, 47 ; on stability of spe 
cies, 294-5 > on principles of 
evolution, 464 ; on the facts of 
organic evolution, 468 ; on “nihil 
per saltum,” 486. 
Hybridisation : 350-2 ; on contin 
uous fertility of offspring, 353-6. 
Increase : in Geometrical Ratio, 43- 
59 ; destruction a check to, 47 ; 
in imported animals and plants, 
5 I *4* . 
Incubating Instinct: 264-7. 
Insects : indiscriminative destruc 
tion of life of, 63 ; accidental 
death amongst, 162-7 5 expanse 
of wing in, 165 ; protective secre 
tion in, 166 ; protective elasticity 
in, 166-7 5 correlation between 
conspicuous colouration and nau 
seous taste of, 207-8 ; tannin in, 
404 ; cause of colouration of, 405, 
406-8; non-useful variation in, 411. 
Neuter: 267-76. 
Walking-stick : protective 
colouration, etc., of, 176. 
Instinct, Animal: 123-30, 220-30; 
instinctive comprehension by in 
sect-eaters, etc., of correlation 
between conspicuous colouration 
and nauseous taste in insects, 
etc., 208-12 ; instinct and intelli 
gence act apart, 230-2 ; evolution 
of instincts precedes intelligence, 
232-41 ; instincts developed by 
Natural Selection, 241-51 ; intel 
ligent animals unobservant of 
actions not intelligently per 
formed yet inherited, 251-63 ; 
loss of, 259-63 ; instincts de 
veloped apart from intelligence, 
263-7 ; instincts acquired by in 
dividuals not inherited, 267-89; 
variation of, 279-85.