250 ROMANCE OF THE INSECT WORLD CHAP. 



combinations are inevitably repeated again and again, 

 and by insects of widely different families. Similarly 

 the patterns that are employed are few and pre- 

 eminently conspicuous and simple. In this manner 

 insect-eating animals are not only readily attracted 

 to the signal, they early and quickly recognize un- 

 palatability or danger as a whole, and probably have 

 not to gain experience through trial of every 

 nauseous species in their locality, an education that 

 would be unpleasant and tiresome to the eaters and 

 costly of life to the insects tested. The frequent 

 repetition of the same colours and patterns in 

 distasteful forms is a necessity, since only a limited 

 number afford the required effect, and the repetition 

 is itself an advantage, and consequently has been 

 encouraged by natural selection. 1 



It would appear to be a difficult matter to 

 distinguish which are Warning Colours. Probably 

 all ornament in mature individuals may be partly 

 attributed to the agency of sexual selection, and has 

 a sexual interpretation. But generally speaking it is 

 easy to distinguish the appearance which has a purely 

 sexual meaning, and that which has been specially 

 modified for other uses as well. The colours pro- 

 duced by courtship are beautiful, more or less 

 blended, the patterns are elegant, whereas, as we have 

 seen, startling and strongly contrasted colours and 

 primitive patterns are evidences of the warning 

 signal; intrinsic beauty gives way before conspicuous- 

 ness and effect. But besides these differences, the 

 particular value of colour may be judged by the 

 1 Poulton. 



