Transparency and colour 53 _Trigonia_ 86 _Tubipora musica_ 54 _Tubularida_ 59 Tylor, A., on Specific change 10 _Vanessa Antiopa_ 76 ---- _atalanta_ 29, 43, 69 ---- _urticæ_ 77 Variation in insects 70 ---- law of 2 ---- simple, in Butterflies 77 _Velella_ 52, 65 Vertebrata, colouration of 88 _Viverridæ_ 94 Wallace, A. R., on sexual selection 5, 6, 14, 15 ---- on colour 29 ---- on abnormal structures 94 Warning colours 4 Wasps 84 Weir, J. Jenner, on variation in insects 78 Weismann, Dr., on Caterpillars 81 Wing of Butterfly, typical 70 ---- patterns of 76 Woodpecker 91 Yellow Archangel 96 Zebra 92 _Zygæna_ 69 [Illustration] [Illustration: Fig. 4.--PYTHON. _Showing vertebra-like markings._] [Illustration: Fig. 5.--TIGER. _The pattern changes at the points lettered._] [Illustration: Fig. 6.--TIGER.] [Illustration: Fig. 7.--TIGER. _Showing supra-orbital nerve mark._] [Illustration: Fig. 8.--TIGER. _Showing cerebral markings, and markings over nerves near the eyes._] [Illustration: Fig. 9.--LEOPARD. _The pattern changes at the points lettered._] [Illustration: Fig. 10.--LEOPARD. _The pattern changes at the points lettered._] [Illustration: Figs. 11, 12.--LEOPARDS' HEADS.] [Illustration: Fig. 13.--LYNX. _The colour changes at the points lettered._] [Illustration: Fig. 14.--LYNX.] [Illustration: Fig. 15.--OCELOT. _Showing changes of pattern at the joints, &c., with enlargement of head-pattern._] [Illustration: Fig. 16.--BADGER. _The colour changes at the points lettered._] [Illustration: Fig. 17.--BEGONIA LEAF.]