There is yet another exceedingly interesting psychical trait to be noticed in the lower animals, especially in insects; I refer to the instinctive habit, letisimulation (letum, death, and simulare, to feign). The word "instinctive" must not be used, however, when this stratagem is to be observed in the higher animals other than the opossum; for many of these animals sometimes make an occasional and a rational use of it, as I will endeavor to show in the next chapter.
FOOTNOTES:
[93] I believe that I am the first to claim the sensual importance of tinctumutation and the sense of direction or the "homing sense." Heretofore they have been regarded, by all authorities as far as I know, as instinctive in character.—W.
[94] Semper, Animal Life, p. 93.
[95] Ibid., p. 88 et seq.
[96] Vide Dewar, "The Physiological Action of Light," Nature, p. 433, 1877; quoted also by Semper, loc. cit. ante, Notes, p. 423. I do not think that the absence of the slight amount of color in the animals reared under the yellow light was due to the "optic current" of Dewar. The microscope showed that the chromatophores were just as large and just as numerous, and that they contained as much pigment, as those reared under the red light. The apparent absence of color was due to tinctumutation.—W.
[97] Karl Semper, Animal Life, p. 422.
[98] Karl Semper, Animal Life, p. 95.
[99] Mr. Gordon Rett has recently called my attention to a blind "angel fish" which shows, most conspicuously, a lack of tinctumutation. This fish was made blind for experimental purposes.—W.
[100] Karl Semper, Animal Life, pp. 95, 96.