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Show 1887.] VALUE OP COLOUR AND MARKINGS IN INSECTS. 205 conspicuous larvae, in every way typical of the strongly coloured group to which Darwin had called the attention of Wallace, and having further tabulated those which become conspicuous on the approach of danger, it is now necessary to add a iew other species which cannot be regarded as typical of the above-mentioned class, but which are not concealed or are very imperfectly concealed by protective colouring, which are more or less freely exposed upon their food-plants, or about which a difference of opinion exists. (Table III., pp. 208, 209.) W e will now consider a few of the conclusions arrived at by a study of the above tables, which give the whole of the experimental evidence (as far as I am aware) upon the precise question originally raised by Darwin. The first and obvious result of the first table is, with only one entirely antagonistic exception, the most complete demonstration of the truth of Wallace's suggestion, that a highly conspicuous appearance would be found to be accompanied by some unpleasant attribute. The exception is very remarkable, as the larva is so highly coloured, and I think the total results of all the experiments will justify us in concluding that the larva of D. euphorbia is unpleasant to some as yet unknown foes, and in all probability that it has been recently distasteful to a larger number. As to the results which bear upon m y own suggestion, it must be observed that the only considerable support is to be expected from the columns of experiments under m y name, because tbe other observers did not enter upon the investigation with this object in view, and therefore did not test whether a distasteful form would be eaten when other food was withheld. It will, however, be found that when this test was applied, in nearly all cases the unpleasant larvae were either swallowed, or a most determined attempt was made to eat them. And there is some incidental support in the other experiments also; for in many instances the larvae were " tasted " before being rejected, and in other cases even stronger confirmation is forthcoming, when the larvae were eaten, although " not exactly relished " (Weismann). Since the above was written, Jenner Weir's experiments in 1886 have been included, and these strongly confirm m y own observations. It may be taken as proved that the continued spread of some distasteful form and the corresponding diminution in edible species would lead to the former becoming the prey of insect-eating Vertebrates; for a point would ultimately be reached, as it was reached in many of mv rxperiments, when hunger would become a stronger stimulus than those lesser prejudices in which a species can very well afford to indulge while palatable food is abundant. This prejudice against peculiarities in taste having been overcome in confinement, there is nothino- in the conditions of natural life which could prevent the same result from being reached, as doubtless it has been reached, ao-ain and again. A comparison of all experiments of this kind ever made with insects will show that the likes and dislikes of insect-eaters are purely relative, and are manifested to a marked extent when they are offered a variety of insects, even when obviously P R O C ZOOL. Soc-1887, No. XV- 15 |