336 THE POPULAR SCIENCE MONTHLY. 



of autumn, in the same plant. It would be impossible to go fully here 

 into the evidence which might be offered on this head ; an immense 

 mass of facts shows us that color is always tending to appear in the 

 leaves which immediately surround the floral organs ; and that this 

 tendency has been strengthened by insect selection of the most con- 

 spicuous blossoms, until it has finally resulted in the brilliant corollas 

 of such flowers as those which we now cultivate in our modern gar- 

 dens. 



But all this takes for granted the very fact with w^hich we are now 

 concerned, the existence and growth of an insect color-sense. How 

 do we know that insects can distinguish colors at all ? For otherwise 

 all this argument must be fallacious, and the presence of bright corol- 

 las must be due to some other cause. 



Of all insects, bees are the most confirmed flower-haunters, and 

 they have undergone the greatest modification in relation to their 

 visits in search of honey. We might expect, therefore, that bees 

 would exhibit a distinct color-sense ; and this is actually the case. 

 Sir John Lubbock's experiments clearly prove that bees possess the 

 power of distinguishing between red, blue, green, and yellow. Being 

 anxious to see whether insects were really attracted by the hues of 

 flowers, he placed slips of glass, smeared with honey, on paper of 

 various colors ; and the bees upon w^hich he experimented soon learned 

 to return to one particular color only, even though both the paper and 

 the honey were occasionally transposed. Thus we have direct evi- 

 dence of the clearest sort that the higher insects do actually perceive 

 the difference between various colors. Nay, more, their perception in 

 this respect appears to be closely analogous to our own ; for while the 

 bees had no difiiculty in discriminating between red, orange, or yel- 

 low, and green, they did not seem to perceive so marked a distinction 

 between green and blue. Now, this fact is very like that which we 

 perceive to hold good with the human eye, for all of us are much more 

 likely to confuse green and blue than any two other hues. 



If, then, bees and wasps, as Sir John Lubbock has shown, and 

 butterflies, as we may infer from other observations, do possess this 

 developed color-sense, we may ask, how did they obtain it ? In all 

 probability it grew up side by side with the growth of bright-hued 

 flowers. Just as those blossoms which exhibited the greatest tendency 

 to display a brilliant whorl of tinted leaves, in the neighborhood of 

 their stamens and pistils, would best succeed in attracting insects, so, 

 in return, th-ose insects whose eyes were most adapted for distin- 

 guishing the pink and yellow blossoms from the green foliage would 

 best succeed in procuring food, and would thus live down their less 

 gifted competitors. 



It may reasonably be asked. How could an animal without a color- 

 sense develop such a faculty by the aid of natural selection alone ? 

 At first sight the question seems indeed a difticult one ; but it is pos- 



