The above method applies also to sweet peas, with these slight modifications. As the anthers ripen relatively sooner in this species, emasculation must be performed at a rather earlier stage. It is generally safe to choose a bud about three parts grown. The interval between emasculation and fertilisation must be rather longer. Two to three days is generally sufficient. Further, the sweet pea is visited by the leaf-cutter bee, _Megachile_, which, unlike the honey bee, is able to depress the keel and gather pollen. If the presence of this insect is suspected, it is desirable to guard against the risk of admixture of {189} foreign pollen by selecting for pollinating purposes a flower which has not quite opened. If the standard is not erected, it is unlikely to have been visited by _Megachile_. Lastly, it not infrequently happens that the little beetle _Meligethes_ is found inside the keel. Such flowers should be rejected for crossing purposes. * * * * * {191} INDEX _Abraxas grossulariata_, 99 "Acquired" characters, 14 Adaptation, 143 Agouti mice, 50 Albino mice, 50 Albinos, nature of, 53 _Amauris_, 144 Analysis of types, 156 Ancestral Heredity, Law of, 13 Andalusian fowls, 70 Axil colour in sweet peas, 93 Bateson, W., 14, 29, 55, 116, 132, 141 Biffen, R. H., 157 Blue Andalusian fowls, 71 Brachydactyly, 171 Bryony, 120 Bush sweet peas, 63 Castle, 132 Cattle, horns in, 86, 166 Colour, nature of, in flowers, 48 Colour-blindness, 117 Combs of fowls, 33, 43 Correns, C., 29, 120 Coupling of characters in gametes, 93 Cuenot, 50, 119 "Cupid" sweet peas, 62 Currant moth, 99 Darwin, C., 10, 65, 147, 163 De Vries, H., 15, 29, 141 Discontinuity in variation, 14 Dominant characters, 18 Doncaster, L., 99 Drinkwater, H., 172 Dutch rabbits, 60 Eggs, 2 Environment, influence of, 137 _Euralia_, 144 Evolution, 10, 85, 139 Eye, in primulas, 55 Eye-colour, in man, 176 Factor, definition of, 31 Factors, interaction of, 42 Fertilisation, 3 Fertilisation, self- and cross-, 163 Fixation of varieties, 153 Fluctuations, 138 Fowls, coloured from whites, 49, 73 Galton, 13, 179 Gametes, nature of, 6 Gregory, R. P., 55, 93 Haemophilia, 176 Hardy, G. H., 147 Heterozygote, definition of, 28 Heterozygote, of intermediate form, 68 _Hieracium_, 27, 132 Himalayan rabbits, 60 Homostyle primulas, 56 Homozygote, definition of, 28 Hooded sweet peas, 89 Horses, bay and chestnut in, 167 Hurst, C. C., 62, 176, 180 Immunity in wheat, 158 Individuality, 135 Inhibition, factors for, 74, 108 Intermediates, 125 {192} Johannsen, W., 160 Lop-eared rabbits, 132 Mendel, 8, 17, 26, 132 Mental characters, 180 Mice, inheritance of coat colour in, 50 Mimicry, 143 _Mirabilis_, 151 Morgan, T. H., 116 Mulattos, 129 Mutation, 83, 138