34 BUTTERFLIES 



warning colors. According to this theory animals which 

 were for any reason not edible by birds and mammals have 

 developed various striking combinations of color such as 

 black and yellow, red and black, or black and white, in 

 order to advertise to their foes their inedible qualities. 

 This theory has been very generally accepted by naturalists 

 and will be found expounded at length in many books pub- 

 lished during the last quarter century. 



The whole subject of the validity of warning coloration 

 has recently been brought up for reconsideration by the il- 

 luminating investigations of Mr. Abbott H. Thayer and 

 discussed at length in the book upon " Concealing Colora- 

 tion" already mentioned. In an appendix to this book 

 dated 1908 Mr. Thayer states that he no longer holds the 

 belief that "there must somewhere be warning colors." 

 He has convincingly shown that a large proportion of the 

 animals which were supposed to be examples of this theory 

 are really illustrations of concealing coloration. But there 

 yet remain various facts which have been conclusively 

 proven that apparently require the theory of warning 

 colors to explain them. Here is another field in which 

 there is a real need for much careful investigation under 

 conditions that are rigidly scientific. 



Along with the theory of warning coloration the theory 

 of mimicry has been propounded. According to this if a 

 butterfly in a given region shows warning coloration, 

 having developed such coloration because it is distasteful 

 to birds and mammals, it may be mimicked by another 

 butterfly in the same region belonging to another group, 

 the latter butterfly being edible, but benefiting by its re- 

 semblance to the distasteful species, because birds or 

 mammals mistake it for the latter and do not attempt to 



