INDEX 



4i9 



Parus atricapillus, climatic ' trends,' 46 

 Parus major, variation in habits, 54 

 Passer, local specific intergradation, 



io 3> ! 5 8 . 

 — , selective elimination, 209 



Passerella, characters of, 289 



— , protective resemblance, 238 



— , ' trend ' in races of, 77 



Pavlov, experiments on rats, 41 



Payne, F., experiments on Drosophila, 



44 

 Payne, N. M., length of life of Micro- 



bracon, 22 

 Peacock, seasonal occurrence of 



Thrinax, 143 

 Pearl, criticism of Weldon on Carcinus, 



— , non-selective elimination of fowls, 



205 

 — , requirements for proof of Natural 



Selection theory, 193 

 Pearl and others, optimum population 



density, 359 

 Pearse, behaviour of Uca, 332 

 Pearson, correlation, ibi 

 — , mathematical treatment of natural 



selection, 218 

 Pectinidae, eyes, 307 

 Pediculus, physiological races, 75, 121 

 Pedigree breeding, in domesticated 



animals, 190 

 Pelseneer, fluctuations in Mollusca, 



19, 20 

 — , influence of chemical factors on the 



Mollusca, 81 

 — , influence of diet on colour of 



Mollusca, 79 

 — , stunting of insular forms of 



Mollusca, 139 

 — , variation, 1 

 — , variation in ectodermal derivatives, 



5 

 Pentatomidae, eaten by birds, 251 



■ — , warning colours, 244 



Pepsinae, generic characters, 277 



Perillns, non-heritable variants, 20 



Perkins, Hawaiian endemics, 135 



■ — , young birds taught what to eat, 



253-54 

 Permutations of characters, 4, 24, 60, 



175 

 Peromyscus, coat-colour on lava fields, 



236 



— , coat-colour on a white sand-spit, 



236-37 

 — , experiments and observations, 39, 



44 . 

 — , hereditary stability of races, 70 



— , interracial character correlations, 



164, 166, 170 



— , species-intergradation, 89, 90 



Peromyscus maniculatus, local populations, 



6 9 ... 



Petersen, co-adaptation of genitalia, 



299 

 Petite espece, 72 



pH of mammalian blood, 353 

 Philanthus, Reinhard's experiments on 



behaviour, 354 

 Philiptschenko, variation, 2 

 Phillips, correlation, 170 

 Philosamia, experiments on, 36 

 — , selective elimination of pupae, 206-7 

 Phratora, experiments on, 36 

 Phrissura, intrageneric mimicry, 256 

 Phymatidae, co-adaptation in forelegs, 



3°9 . 



Physico-chemical processes, in develop- 

 ment, 362 



, in living organisms, 273 



Physiological categories, 73 

 Physiological races, 74, 119, 303 



, hereditary stability of, 5 



, in Arthropods, 5 1 



Picidae, application of Allen's Law, 



Pickford, characters of earthworms, 289 

 Pictet, experiments on Lymantria, 36 

 — , voltinism in Lasiocampa, 144 

 Pierce and Metcalfe, genitalia of 



Cnephasia and Epiblema, 154 

 Pieris, change in population, 213 

 — , experiments on, 37 

 — , selective elimination of pupae, 203 

 Pigeons, determinate evolution, 325 

 Pilsbry, on subspecies, 67 

 Pilsbry and others, races of Partula, 70 

 Plaice, races of, 59 

 Planarians, copulatory styles, 297 

 Planorbis, spread of, 322 

 Plasmons, 23 

 Plate, breeding season of Crangon and 



Orchestia, 145 

 — , evidence for Natural Selection 



theory, 186 

 Pleistocene species, comparison with 



modern, 132-33 

 Plesiocoris, change of habits, 53 

 Plough, sterility in Ascidians, 157 

 Plunkett, criticism of Harrison and 



Garrett's work, 30 

 Plutella, experiments, 38 

 Pocock, baculum of mammals, 297 

 — , scent-producing organs of mammals, 



293 

 — , stunting of insular form of Tiger, 



139 

 — , Tiger paler in north, 241 



Pocota, mimicry of bees, 257 



Polistes, climatic ' trend,' 50 



Polymorphism, bearing on evolution 



of dominance, 229 



