52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



D is ctis si on. —It is obvious from the available data on enemies of 

 Neuropteroidea that the small or rare groups have few, the large and 

 abundant families many foes, the result that would be predicted with 

 " protective adaptations " discounted. The group most numerous in 

 species and individuals, namely the caddisflies, has the most enemies, 

 and their larvae, said to be well defended from enemies, fornj one of 

 the staple elements of the food of fresh-water fishes all over the globe, 

 as well as a favorite prey of aquatic birds. 



LEPIDOPTERA ( MOTHS, BUTTERFLIES) 



Protective adaptations.— In the space that can be devoted in this 

 paper to protective adaptations of Lepidoptera it is impossible to do 

 more than call attention to general aspects of theoretical considera- 

 tions, since what has been written on the subject would fill many 

 volumes. This flood of literature is due principally to the fact that 

 Lepidoptera have been regarded as the chief examples of the phe- 

 nomena of warning colors and of mimicry, subjects that have been 

 expounded and discussed at great length. 



Warning coloration, it need hardly be stated, designates the con- 

 spicuous, often highly contrasted, patterns, which it is held may be 

 assumed with relative impunity by tough, distasteful, or dangerous 

 species. Batesian mimicry is the more or less pronounced resemblance 

 to these species by others supposedly less qualified to cope with the 

 struggle for existence, while Mullerian mimicry is mutual approach 

 in appearance by species all of which belong to " specially protected " 

 groups. As remarked in my 1912 paper, these theories were chiefly 

 built up at a time when there was almost complete ignorance of the 

 actual feeding habits of predacious animals, and attempts to secure 

 evidence on the subject by experiment were in most cases characterized 

 by a singular lack of appreciation of the vital factors involved and of 

 realities in nature. 



The following statement by Alfred Russell Wallace gives the gist 

 of the principal nearctic instances of mimicry among Lepidoptera : 

 " In North America, the large and handsome Danais archippus with 

 rich reddish-brown wings is very common, and it is closely imitated 

 by Limenitis misippus, a butterfly .... which has acquired a color 

 quite distinct from that of the great bulk of its allies. In the same 

 country there is a more interesting case. The beautiful dark bronzy- 

 green butterfly, Papilio philcnor, is inedible both in larva and perfect 

 ■insect, and it is mimicked by the equally dark Limenitis Ursula. There 

 is also in the Southern and Western States a dark female form of the 



