416 



EVOLUTION AND ANIMAL LIFE 



many examples of this clever artifice of Nature to protect her 

 children. 



If the field student may be relied on to note and record a 

 long list of insects colored and marked so as to harmonize well 

 with their general environment or with some specific part of it, 

 he may also be relied on to bring in a list of opposit es : a record 

 of bizarre and conspicuous forms, colored with brilliant blues 

 and greens and streaked and spotted in a manner utterly at 

 variance and in contrast with the foliage or soil or bark or what- 

 ever is the usual environment of the insect. The great red- 

 brown monarch butterfly and its black-striped green and 

 yellowish larva, the tiger-banded swallowtails, the black and 



FIG. 200. Ladybird beetles, conspicuously colored and marked. 



yellow wasps and bees, the ladybird beetles with their sharply 

 contrasting colors, the brilliant green blister beetles, the striped 

 and spotted chrysomelids - - in all these and many others 

 there can be no talk of protective resemblance. If only such a 

 paradoxical theory as protective conspicuousness could be 

 established, then these colors and markings might well be 

 explained by it. 



Exactly such an explanation of brilliant color and contrast- 

 ing markings is afforded by the theory of warning colors. It- 

 has been conclusively shown, by observation and experiment 

 by several naturalists, that many insects are distasteful to 

 birds, lizards, and other predaceous enemies. This is so be- 

 cause the blood lymph or some specially secreted body fluid of 

 these insects contains an acrid or ill-tasting substance so that 

 birds will not, if they can recognize the kind of insect, make 

 any attempt to catch or eat one. This letting alone is un- 



