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SCIENCE PROGRESS 



orange by yellow will have the same effect by removing the 

 colour away from the conspicuous red end of the spectrum, so 

 that these exceptions go to prove the rule. 



This completes the consideration of the Indian Lepidoptera. 

 A short examination of birds will now be made, and will consist 

 chiefly in testing certain predictions which have already been 

 made. 



When dealing with solid objects, it is necessary to take into 

 account chiaroscuro, because colours will have quite different 

 value according as to whether they are in high illumination on 

 the back of the bird, or in low, on its ventral surface. It has 

 already been predicted that for this reason one would expect 



