Retinaculum, xii Salivary vessels, xiii Serrate, xi Sexual selection, xvi Species, origin of, xiii Spinneret, x Spinning vessels, x Spiracles, ix Stalking of veins, xii Struggle for existence, xiv Sucking stomach, xiii "Survival of the Fittest", xiv Termen, xi Tibia of imago, xiii " of larva, ix Tongue, xi Tornus, xii Unipectinated, x Variation, xiii "Vegetable caterpillar", 132 Veins of wings, xii Ventriculus of imago, xiii " of larva, x Warning colours, xv Wings, xi SPECIAL INDEX. Names of Groups are printed in capitals (CARADRININA, &c.). " Families, in small capitals (ARCTIADÆ, &c.). " Sub-families, in sanserif italic (_Poliades_, &c.). " Genera, in roman beginning with a capital (Agrotis, &c.). " Species, in roman (annulata, &c.). " Synonyms, in ordinary italic (_doubledayi_, &c.). PAGE