_Pachylia Ficus_, early stages of larva, 232.
Packard, insect phylogeny, 493.
Pangenesis, theory of, 668.
_Papilio._ _P. Ajax_, seasonal forms, 30;
_P. Turnus_, a dimorphic form, 32;
_P. Machaon_ and _Podalirius_, seasonally dimorphic in Spain and
Italy, 74;
_P. Ajax_, experiments with, 126;
_P. Merope_, young larva, 166;
_P. Homerus_, young larva, 167;
_P. Machaon_, larva rejected by lizards, 339.
Parallelism, phyletic, in metamorphic species, 390;
phyletic, law of, 510.
_Pararga Ægeria_, sexually dimorphic, 68;
climatic variation of, 68.
Pascoe, F. P., “Zoological Classification” referred to, 488, 498.
_Pelobates_, experiments with tadpoles, 607.
_Pergesa Mongoliana_, larva, 194.
_Philampelus achemon_ and _P. satellitia_, larvæ, 523;
_P. labruscæ_, larva, 195;
_P. vitis_, and _P. anchemolus_, larvæ, 232.
Philosophy, function of, 640.
_Phyciodes Tharos_ and _P. Marcia_, seasonal dimorphism of, 4;
experiments with, 140.
Phylogeny, conclusions from, 270;
and ontogeny of Sphinx-markings, 177;
of insects, 493.
_Pierinæ_, seasonal dimorphism of, 13;
analogous seasonal dimorphism in, 60, 108;
experiments with, 122.
_Pieris Napi_, experiments with, 13;
summer form the younger, 29;
reversion of, caused by mechanical vibration, 38;
var. _Bryoniæ_, the potential winter form, 39;
experiments with this var., 40;
this var. the parent form of _Napi_, 41;
a climatic var., 41;
very variable, 43;
variability due to crossing, 43;
var. _æstiva_ more variable than var. _vernalis_, 43;
_P. Napi_, summer and winter forms compared, 56;
incongruence in this species, 457;
_P. Krueperi_, seasonal dimorphism of, 78;
_P. Brassicæ_, larva rejected by lizards, 337;
constant in three stages, 405;
photographic sensitiveness of pupa, 405;
_P. Napi_, variable in two stages, 405.
Plants, cultivated, 107;
sterility of reverted, 596.
Plastidule theory, 667.
_Plebeius amyntas_ and _P. polysperchon_, seasonal dimorphism, 2;
_P. Alexis_, do., 3;
_P. pseudargiolus_ and _P. violacea_, do., 4;
_P. agestis_, do., 50;
polymorphism of females in this genus, 251.
Pluvial period, 621.
Polar animals, colour of, 658, 660.
_Polyommatus phlæas_, distribution and climatic variation, 49;
seasonal dimorphism, 50;
Italian summer and winter forms compared, 55.
_Polyptychus dentatus_, larva, 244.
Ptarmigan, seasonal colours of, 6.
_Pterogon_, larvæ of, 255;
_P. ænotheræ_, larva, 256.
_Pulmonifera_, functional change in lungs, 590.
_Pygæra bucephala_, larva rejected by lizards, 337.