TEE COLORS OF ANIMALS AND PL J NTS. 



527 



only exposed at night contrast remarkably with 

 the sombre tints of the upper-wings which are 

 more or less exposed to the various colors of 

 surrounding Nature. 



We find, then, that neither the general influ- 

 ence of solar light and heat, nor the special ac- 

 tion of variously-tinted rays, are adequate causes 

 for the wonderful variety, intensity, and com- 

 plexity of the colors that everywhere meet us 

 in the animal and vegetable world. Let us, there- 

 fore, take a wider view of these colors, grouping 

 them into classes determined by what we kuow 

 of their actual uses or special relations to the 

 habits of their possessors. This, which may be 

 termed the functional or biological classification 

 of the colors of living organisms, seems to be 

 best expressed by a division into five groups as 

 follows : 



1. Protective colors. 



Animals. 2. 'Warning colors. 



3. Sexual colors. 

 v 4. Typical colors. 

 Plants.... ' 5. Attractive colors. 



r 



a. Of creatures spe- 



cially protected. 



b. Of defenseless creat- 



ures, mimicking a. 



The nature of the first two groups, protective 

 and warning colors, has been so fully detailed 

 and illustrated in my chapter on "Mimicry and 

 other Protective Resemblances among Animals " 

 (" Contributions to the Theory of Natural Selec- 

 tion," page 45), that very little need be added 

 here except a few words of general explanation. 

 Protective colors are exceedingly prevalent in 

 Nature, comprising those of all the white arctic 

 animals, the sandy-colored desert forms, and 

 the green birds and insects of tropical forests. 

 It also comprises thousands of cases of special 

 resemblance — of birds to the surroundings of 

 their nests, and especially of insects to the bark, 

 leaves, flowers, or soil, on or amid which they 

 dwell. Mammalia, fishes, and reptiles, as well as 

 mollusca and other marine invertebrates, present 

 similar phenomena; and the more the habits of 

 animals are investigated, the more numerous are 

 found to be the cases in which their colors tend 

 to conceal them, either from their enemies or 

 from the creatures they prey upon. One of the 

 last-observed and most curious of these protec- 

 tive resemblances has been communicated to me 

 by Sir Charles Dilke. He was shown in Java a 

 pink-colored mantis, which, when at rest, exactly 

 resembled a pink orchis-flower. The mantis is a 

 carnivorous insect which lies in wait for its prey, 

 and by its resemblance to a flower the insects it 

 feeds on would be actually attracted toward it. 



This one is said to feed especially on butterflies, 

 so that it is really a living trap and forms its own 

 bait ! All who have observed animals, and espe- 

 cially insects, in their native haunts and atti- 

 tudes, can understand how it is that an insect 

 which in a cabinet looks exceedingly conspic- 

 uous may yet, when alive in its peculiar atti- 

 tude of repose and with its habitual surround- 

 ings, be perfectly well concealed. We can hardly 

 ever tell, by the mere inspection of an animal, 

 whether its colors are protective or not. No one 

 would imagine the exquisitely beautiful cater- 

 pillar of the emperor-moth, which is green with 

 pink, star-like spots, to be protectively colored ; 

 yet when feeding on the heather it so harmonizes 

 with the foliage and flowers as to be almost in- 

 visible. Every day fresh cases of protective 

 coloring are being discovered even in our own 

 country, and it is becoming more and more evi- 

 dent that the need of protection has played a 

 very important part in determining the actual 

 coloration of animals. 



The second class — the warning colors — are 

 exceedingly interesting, because the object and 

 effect of these is, not to conceal the object, but 

 to make it conspicuous. To these creatures it is 

 useful to be seen and recognized, the reason be- 

 ing that they have a means of defense which, if 

 known, will prevent their enemies from attacking 

 them, though it is generally not sufficient to save 

 their lives if they are actually attacked. The 

 best examples of these specially protected creat- 

 ures consist of two extensive families of butter- 

 flies, the Danaida? and Acrseidae, comprising many 

 hundreds of species inhabiting the tropics of all 

 parts of the world. These insects are generally 

 large, are all conspicuously and often most gorge- 

 ously colored, presenting almost every conceiv- 

 able tint and pattern ; they all fly slowly, and 

 they never attempt to conceal themselves ; yet 

 no bird, spider, lizard, or monkey (all of which 

 eat other butterflies), ever touches them. The 

 reason simply is that they are not fit to eat, their 

 juices having a powerful odor and taste that is 

 absolutely disgusting to all these animals. Now, 

 we see the reason of their showy colors and slow 

 flight. It is good for them to be seen and recog' 

 nized, for then they are never molested ; but if 

 they did not differ in form and coloring from 

 other butterflies, or if they flew so quickly that 

 their peculiarities could not be easily noticed, 

 they would be captured, and though not eaten 

 would be maimed or killed. As soon as the 

 cause of the peculiarities of these butterflies was 

 recognized, it was seen that the same explaua- 



