1912.] NATURAL SCIENCES OF PHILADELPHIA. 305' 



of his own experiments Poulton says: "Wallace had predicted that 

 brilliantly colored and conspicuous insects would be refused by the 

 ordinary vertebrate enemies of their class." This statement, which 

 was a "bull" from the very beginning (inasmuch as we cannot 

 reckon as enemies of an insect those animals that refuse to eat it) 

 is wrongly stated by Poulton in both of the above cases. Wallace's 

 original suggestion, as reported in Proc. Ent. Soc. London, 1867, 

 p. lxxxi, is that, "as a rule, the brilliantly colored larvse were those 

 which were distasteful to birds." Poulton further twists this in his 

 table headings to a suggestion "that brilliant and conspicuous 

 larvae would be refused by some at least of their enemies," a much 

 later modification of Wallace's statement. 



However, this later claim would be admitted without argument 

 did we accept Poulton's usage of the term enemies as including 

 practically all insectivorous animals. Even if there were no other 

 factors involved, the relative sizes of the larva? and of various insec- 

 tivorous animals in themselves establish limits to the number of 

 predators upon a certain form; thus numerous large larvse will be 

 free from attacks of all but a small proportion of insectivorous foes. 

 Very small larva?, on the other hand, will be overlooked by many 

 predators. That is, considerations entirely aside from coloration 

 will limit the number of enemies of any given form. It is evident 

 that all vertebrates cannot be enemies of the same insect; enemies 

 and prey form indefinite groups that intermesh in a multitude of 

 combinations. Consequently, an insect cannot be said to be pro- 

 tected, because certain vertebrates more or less ignore it, when they 

 perhaps have no opportunity and certainly in many cases no necessity 

 for feeding on it in the wild state. 



Poulton first tabulates the results of experiments with eighteen 

 species of "undoubtedly conspicuous larvse," and concludes: "The 

 first and obvious result of the first table is, with only one entirely 

 antagonistic exception, the most complete demonstration of the 

 truth of Wallace's suggestion that a highly conspicuous appearance 

 would be found to be accompanied by some unpleasant attribute" 

 (p. 205). Upon close inspection of this table, we find there are two, 

 not one, species that are not shown to be distasteful to any animal, 

 namely, Deilephila euphorbice and Lasiocampa pini; eight not refused 

 by anything are included because they were disregarded by birds. 

 The writer has explained above why disregard cannot be accepted 

 as a test at all. The inadvisability of so doing is shown by the fact 

 that at least three of these eight species of larvse, namely, Orgy in 



