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Show 1895.] COLOUR-VARIATIONS OP A BEETLE. 857 In the Table the frequency with which specimens of each colour were taken in cop. is recorded. In each case special care was taken to see that the pair were actually coupled, and none were counted for this purpose unless they remained attached when removed from the bush. It will be seen that the numbers agree very fairly well with those that they should be if the coupling occurred by simple chance, for the number of each colour found coupled bears about the same proportion to the whole number found coupled that would be expected according to the frequency of that colour. It is clear that we have here an example of a species whose members exhibit variation in several different respects, and that the variations occur in such a way that the individuals must be conceived as grouped round several subtypical forms. There is thus not one normal for the species but several. Next, though all are living in the same locality under the same conditions, and though they breed freely together, these various forms are commoner than the intermediates between them *. Upon the significance of such a case I have sufficiently commented elsewhere 2. One point may be of interest to students of the adaptation of the colours of animals to their surroundings, namely the fact that while the red-spotted forms are strikingly conspicuous objects the striped greenish-grey forms resemble so nearly the colour of the twigs of the Spartium that it is impossible hot to remark the likeness. If they were the only form known, the case might well be used as an illustration of a protective coloration. The red-spotted forms present some superficial likeness to the common Lady-bird (C. bipunctata), a creature which exudes an acrid juice, and whose colour has naturally been classed among " warning colours." The Goniodena does not, so far as I know, possess any such irritant properties, but I have no information as to its enemies. As Coccinella bipunctata is not very common on the Spartium, probably no one will suggest that we have here an example of protective mimicry. I may mention, however, that Coccinella septempuyidata, the larger scarlet species, occurs in vast quantities mixed with Goniodena. Whether anyone would consider the resemblance to this species sufficiently close to constitute mimicry, I cannot say. Speaking of the excessive variability of the colour of C. clecem-punctata and of the no less striking constancy of C. septempunctata, which lives with it, I remarked3 that to ask us to believe that the colour of the one is constant because it matters to the animal, and that the other is variable because it does not matter, is to ask us to abrogate reason. Mr. A. B. Wallace, in a recent article4, takes exception to this comment, saying that he, for his part, is of this 1 As was pointed out, this is not true of the black variety. 2 ' Materials for the Study of Variation,' 1894, pp. 48, 72, &c. s L. c. p. 572. 4 ' Fortnightly Beview/ March 1895, p. 436. |