to us) may be separated, for our purposes, into several main groups, — such 

 as that of sedentary and that of aerial species. The division is somewhat 

 arbitrary, since practically all butterflies are strong of wing, and there is such 

 a multitude of intermediates connecting the two types that it is impossible to 

 draw a sharp line between them; nevertheless, the terms cover, in the aggre- 

 gate, an essential difference of characteristics. Among the sedentary species, 

 then, occur all the most highly wrought, minutely detailed "cryptic" pat- 

 terns (a good many of which have been recognized as such by naturalists in 

 general). They are worn by butterflies which pass most or at least very 

 much of their time at rest, sitting motionless, with wings — in most cases — 

 folded perpendicularly over their backs. Some of them are developed mimet- 

 ically, even to an extraordinary degree — e. g., the, famous leaf-mimicking 

 Kallima inachis, of India. There are many other pronounced though less 

 extreme cases of whole-leaf mimicry among butterflies, not only in the genus 

 Kallima, but in nearly allied as well as in some remote genera— and even 

 among restless 'aerial' species. One such, which I believe has never been 

 recorded, is that of the abundant and familiar South American Heliconius 

 melpomene. On wing amidst the uniformly bright-green lower foliage of the 

 tropical woods, it is as often conspicuous as any patterned butterfly could 

 well be. [The gaudy costume of this red-and-black Heliconius is evidently one 

 more example of coloration adapted to the wearer's moments of greatest danger. 

 Haunting, while on wing, the thickest foliage, where birds cannot easily catch 

 it, it is probably most in danger when intently feeding among flowers. (At 

 such times butterflies sometimes allow themselves actually to be plucked off 

 their perch by one's thumb and finger.) Probably this Heliconius finds such 

 an intoxicating feast in the tops of certain great flowering trees that it there 

 becomes an easy prey to any birds that want it.]* But in its nightly roosting 

 (begun in the early twilight), it is a leaf -mimic, of no mean achievement. 

 It roosts — as we have seen it — gregariously, several individuals (three to ten 

 or more) occupying the same leafless twig, beneath which, at pretty regular 



* Interpolation by A. H. Thayer, 

 214 



