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