J887.] VALUE OF 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 few 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.) 



We 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 demonstra- 

 tion 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 jD. euphorbice 

 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 my own suggestion, it must be observed 

 that the only considerable support is to be expected from the 

 columns of experiments under my name, because the 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 larv« 

 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 larvoe were " tasted " 

 before being rejected, aud in other cases even stronger con- 

 firmation is forthcoming, when the iarvse 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 my own observations. 



It may be taken as proved that the continued si)read of some dis- 

 tasteful 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 my experiments, 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 

 nothing in the conditions of natural life which could prevent the 

 same result from being reached, as doubtless it has been reached, 

 again 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 



Proc. Zool. Soc— 1887, No. XV. 15 



