Heliconius erato, forms of, 122,164 Helix lapicida, local variation of, 126 striata, 127 Heripensis, 127 Caespitum, 127 trochoides, 127 nemoralis and hortensis, 128 Helminthophila, geographical races of, 157 Hemerophila abruptaria, melanic, 142 Hepialus humuli, in Shetland, 119 Heterostyle plants, 236 Hieracium, 9 Himantopus, 234 Homoeosis, 68 Hybernia progemmaria, 139 Hybrids, sterility of, 233 et seq. Incompatibility between certain allied species, 239 Individual, geometrical independence of, 58 Inhibiting Factors, 95 Intermediates, nature of, 131,135 Isolation, consequences of, 118 Lacerta muralis, Kammerer's experiments on, 209 fiumana, 210 Leptinotarsa, Power's experiments on, 218 Limbs, extra, in pairs, 72 Limnaea, sinistral, 134 Linaria vulgaris, self-sterility, 239 Loasa fruits, right and left, 57 Lobster, extra claws, 76 Locality, variation connected with, 14,118,146 et seq.,208 Lumbricus, regeneration, 77 Lychnis dioica and vespertina, inter-relations of, 18 macrocarpa, possibly a common parent of, 19