Color and Pattern and their Uses 585 



lying longitudinally along green grasses simply merge into the color scheme 

 of their environment. The gray moth rests unperceived on the bark of 

 the tree-trunk. Hosts of insect kinds do really thoroughly harmonize with 

 the color-pattern of their usual environment, and by this correspondence 

 in shade and marking are difficult to perceive for what they are. Now 

 if the eyes that survey the green foliage or run over the gray bark are those 

 of a preying bird, lizard, or other enemy of the insect, it is quite certain — 

 our reason tells us so insistently — that this possession by the insect of color 

 and pattern tending to make it indistinguishable from its immediate environ- 

 ment is advantageous to it: advantageous to the degree of often saving its 

 life. Now such a use of color and pattern is obviously one which can be 

 wide-spread through the insect class, and may be to many species which 

 lead lives exposed to the attacks of insectivorous animals of large — even 

 of life and death — importance. And naturalists, most of them at least, 

 believe that this kind of usefulness is real, and that it is the principal clue 

 to the chief significance of color and pattern. And this not alone in the 

 case of insects, but of most other animals as well. 



From this point of view, namely, that color-patterns may be of advantage 

 in the struggle for existence, just as strength, swiftness, and other capacities 

 and conditions are, the specialization and refinement, all the wide modifica- 

 tion and varietv of colors and patterns, are explicable by the hypothesis of 

 their gradual development in time through the natural selection of naturally 

 occurring advantageous variations. On this basis, such special instances 

 of resemblance to particular parts of the environment, as that shown by 

 Kallima in its likeness to a dead leaf, and Diapheromera in its simulation 

 of a drj', leafless twig, are simply the logical extremes of such a line of speciali- 

 zation. 



But the nature observer may be inclined to ask how such brilliant and 

 bizarre color-patterns as those of the swallowtail-butterflies and the tiger- 

 banded caterpillars of Anosia can be included in any category of "protective 

 resemblance" patterns. They are not so included, but are explained inge- 

 niously by an added hypothesis called that of "warning colors," while for 

 the striking similarities of pattern often noted betvi'een two unrelated con- 

 spicuously colored species still another clever hj-pothesis is proposed. In 

 these cases it is not concealment that the color-pattern effects, but indeed 

 just the opposite. Since the pioneer studies of Bates and Wallace and Belt, 

 naturalists have been observing and experimenting and pondering these 

 exposing as well as these concealing conditions of color and pattern, and 

 they have proposed several theories or hv'potheses explanatory of the various 

 conditions. These hypotheses are plausible; but they are much more than 

 that; they are each more or less well backed up by observation and experi- 

 ment, and some of them have gained a large acceptance among naturalists. 



