258 



THE AMERICAN NATURALIST 



[Vol. LI 



nor, when at rest on leaves, did they appear to be molested by lizards 

 or the predaceous flies of the family Asilidae, which were very often 

 seen pouncing on butterflies of other families. If they owe their flour- 



dition, should be disguised in their dress, and thus share their immunity. 



Bates himself points out the fact that "some of the 

 mutual resemblances of the HeliconidsB seem not to be due 

 to the adaptation of the one to the other, but rather, as 

 they have a real affinity, ... to the similar adaptation 

 of all to the same local, probably inorganic conditions." 

 Thus the application of his hypothesis was limited from 

 the beginning. 



Fritz Miiller^ showed how those instances of resem- 

 blance which his predecessor ascribed to the influence 

 of Lamarckian factors might be aligned with the Darwin- 

 ian hypothesis. In Meldola's"* translation of his original 

 paper his idea is expressed as follows : 



Wliat benefit can one siiecies derive from rese.nbling another, if each 

 is protected by distastefulness f Obviously none at all, if insectivorous 



species which' arc tasteful or' distasteful to them— if an unconscious in- 



avoid. But if each single bird has to learn this distinction by ex- 

 perience, a certain number of distasteful butterflies must also fall vic- 

 tims to the inexperience of the voung enemies. Now if two distasteful 

 species arc sufficiently alike to be mistaken for one another, the ex- 



Recent years have been marked by a tendency upon 

 the part of some observers-'"' to extend the bounds of the 

 Miillorian association^, until in a given fauna a large pro- 

 ))()rti()n of tlic iiix'cts whidi sliow the same color com- 

 Iiiii;i{ii)n art' included in one bionomic group. Scores of 

 -pccic- li;i\f. indeed, been assigned to some, and it has 



