OUR DEBT TO INSECTS. 343 



insect8 differ greatly from one another in their taste for color. Prob- 

 ably we shall be right if we say that the most aesthetic among them 

 all are the butterflies, and next the bees — these two classes having 

 undergone the most profound modifications in adaptation to their 

 flower-haunting life — and that the carrion-flies and wasps bring up the 

 rear. 



Is there any evidence, however, that insects ever notice color in 

 anything else but flowers ? Do they notice it in their own mates, and 

 use it as a means of recognition ? Apparently they do, for Mr. Dou- 

 bleday informed Mr. Darwin that white butterflies often fly down to 

 pieces of white paper on the ground, mistaking them doubtless for 

 others of their species. So, too, Mr. Collingwood notes that a red 

 butterfly, let us say, nailed to a twig, will attract other red butterflies 

 of the same kind, or a yellow one its yellow congeners. When many 

 butterflies of allied species inhabit the same district, it often happens 

 that the various kinds undergo remarkable variation in their coloring 

 so as to be readily recognizable by their own mates. Again, Mr. Pat- 

 terson noticed that certain blue dragon-flies settled in numbers on the 

 blue float of a fishing-line, while two other species were attracted by 

 shining white colors. On the whole, it seems probable that all insects 

 possessing the color-sense possess also a certain aesthetic taste for colors. 



Indeed, it is difficult to see how it could be otherwise. Whenever 

 an animal exercises a faculty much, the exercise comes to have pleas- 

 ant feelings attached to it ; and this is especially the case with all 

 sense-organs. Creatures which live on honey love sweet things : car- 

 nivores delight in the taste of blood. Singing birds listen with inter- 

 est to musical notes : and even insects will chirp in response to a chii*p 

 like their own. So, creatures which pass all their lives in the search for 

 bright flowers must almost inevitably come to feel pleasure in the per- 

 ception of brilliant colors. This is not, as so many people seem to 

 think, a question of relative intellectual organization : it is a mere 

 question of the presence or absence of certain sense-centers. 



But it may finally be urged that, even though insects recognize and 

 admire colors in the mass, they would not notice such minute and deli- 

 cate patterns as those on their own wings. Let us see what evidence 

 we can collect on this head. First of all, insects have not only pro- 

 duced the petals of flowers, but also the special markings on those 

 petals. Kow, these markings, as Sprengel pointed out a century since, 

 bear a constant reference to the position of the honey, and are in fact 

 regular honey-guides. If one examines any flower with such marks 

 upon the petals, it will be found that they converge in the direction 

 of the nectaries, and show the bee or butterfly whereabout he may 

 look for his dinner. Accordingly, they must have been developed by 

 the gradual action of insects in fertilizing most frequently those flow- 

 ers which offered them the easiest indication of where to go for food. 

 Unless insects noticed them, nay more, noticed them closely and accu- 



