Variations, necessary, their constant presence, [26] et seq., [31] et seq., [61];

generally, [3], [11]-[14], [61], [71] et seq.

Waagen, [72].

Wallace, [11], [25], [29], [51], [66], [81].

Weldon, [36].

Whale, hind leg of, [42], [56], [80].

Whitman, C. O., [53].

Wiesner, [40].

Wigand, Albert, [11], [63].

Wings of butterflies, [14] et seq., [47]-[52], [56].