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Show 1837.] VALUE OF COLOUR AND MARKINGS IN INSECTS. 231 always) more abundant species which it resembles. In the former classes of resemblance we have groups of two or more conspicuous forms all possessing unpleasant attributes, which become convergent in external appearance, or which maintain an initial uniformity, and in either case are mutually benefited by the process. In the latter class the resemblance would be a source of danger to the mimicked species if the edibility of the mimicking species were discovered ; and the experiments detailed in tbe present paper show how likely it is that such qualities would be discovered if tbe latter species became relatively abundant. Nevertheless, until the discovery ivus made, the mimicry would be an advantage to both species, for the reasons already adduced. In the following Table the colours of conspicuous insects are tabulated, i. e., those contained in Tables I. and IV., excluding S. fuciformis and the conspicuous larva of L. pini, the latter being omitted because I have never seen a specimen, and because the appearance differs greatly in the various figures I have been able to consult (see Table A, pp. 232-235). I have described the colours of the imagos at rest to correspond with the larvse and pupse ; in flight the following effects are seen:- Imagos of Wasp, Bombus, Nomada marshamella, E. jacobaa, A. filipendula, A. grossulariata, the two Coccinellidse, Telephorus and Chrysomela, would show much the same colours as at rest, although in E. jacobaa and A. filipendulce the red would be in larger amount because of the under wings, and in the Coccinellidse, Telephorus and Chrysomela, the black would be in far larger amount because of the body. The imagos of S. menthastri, S. lubricipeda, and P. auriflua would hardly show the black spots in flight, but would appear whitish, yellowish, and white respectively. This comparison is exceedingly interesting if it is remembered that the colours which are repeated again and again are those which are known to produce the greatest effect. Thus the greatest possible contrast is afforded by black and white, and next to this by black (or some very dark colour) and yellow, orange, or red, the brightest colours in the spectrum, which possess a far higher illuminating-power than any of the others. Hence we find that the colours of all the conspicuous insects which have been tested are in all except five cases included in tbe short list given above. And these five only differ in the inclusion of blue in one case, and of green in the other four cases. Hence we probably see that in addition to the advantage gained by convergence which has been alluded to above, benefits have been derived from the colours which have been employed ; and as the choice of the most conspicuous colours is limited, it is seen that a certain amount of similarity must follow incidentally from the number of forms of life among which the few combinations are divided. Hence convergence has been aided and perhaps given its startin°--point by tbe action of another principle of coloration also favoured by natural selection, and leading in the same direction as convergence itself (see Table B, pp. 236, 237). Just as similarity in colours was favoured by the limited number of suitable combinations, so there are a few eminently conspicuous |