18S7-] VALUE OF COLOUR AND MARKINGS IN INSECTS. 26/ 



8. A few, probably transitioual, forms may be unconcealed, and 

 yet not very conspicuous ; these may possess unpleasant qualities or 

 may be eaten readily. 



9. The likes and dislikes of insect-eaters are purely relati%'e, and 

 if pressed with hunger the most disagreeable and higlily conspicuous 

 insects may be eaten. Hence probably the relatively small number 

 of species which adopt such a means of defence. 



10. It seems probable that when one Vertebrate eats an unpleasant 

 insect, and another refuses it, the former has conquered its prejudices, 

 having originally disliked the insect. 



11. In the sexually mature forms warning colours can be distin- 

 guished from sexual colours by their distribution on the surface of 

 the body, by the way in which they are displayed in flight, by their 

 type of pattern, and the colours employed. The sexual colours and 

 patterns are beautiful, the others conspicuous. Nevertheless, to the 

 modified taste of a highly conspicuous insect, the warning colours 

 probably possess value as sexual adornments. 



12. The conspicuous appearance has relation to the injury which 

 would be inflicted by the experimental "tasting" of certain enemies, 

 e. g. Birds and Lizards ; but nevertheless, other enemies, which do not 

 inflict injury in tasting, e. g. Frogs, have taken advantage of the 

 warning colours to a limited extent. 



13. Insects which evade their enemies by protective resemblance 

 and attitude, rapid movements, or habits of concealment, &c., are 

 generally palatable, but they may often possess an unpleasant taste 

 or smell which may or may not protect them from enemies. 



14. In a very small number of species the most perfect form of 

 protective resemblance may coexist with a most unpleasant taste. 



1 .5. Mere size alone may protect a species against certain of its 

 smaller foes. 



16. Comparing the different stages in Lepidoptera, unpleasant 

 attributes appear to arise in the larval stage, and they then often 

 pass through the two other stages attended or unattended, in one or 

 both, by warning colours. 



17. The most highly specialized protective colours probably also 

 possess value as sexual adornment. 



Considerably over 100 species or stages of insects have been ex- 

 perimented upon, and the results are described in the Tables given 

 in this paper. Looking at these results as a whole, it is seen that 

 the various defensive measures may exist in almost any combination, 

 and that the present condition of a species is in large part an out- 

 come of the means of protection in past strugo;les. Just as in a 

 long-contested battle the same position may be taken, lost, and re- 

 taken, but never held a second time with quite the same significance 

 as before, because of all that has happened as a result of the previous 

 occupation and of all that has happened since in other parts of the 

 field, so in the ever-changing relations between a species and its 

 enemies the structural and functional means of defence may be taken 



