344 THE POPULAR SCIENCE MONTHLY. 



rately, they could never have grown to their present definite correla- 

 tion with the nectary, a correlation which, Mr. Darwin says, first con- 

 vinced him of the reality of their function. " I did not realize the 

 importance of these guiding marks," says Sir John Lubbock, "until, 

 by experiments on bees, I saw how much time they lose if honey 

 which is put out for them is moved even slightly from its usual place." 

 In short, insects, like men, are creatures of habit. How complicated 

 these marks sometimes become, we can see in most orchids. 



Again, the attention insects pay to comparatively small details of 

 color and form is clear enough from the mimicry which sometimes 

 occurs among them. In some instances, the mimicry is intended to 

 deceive the eyes of higher animals, such as birds or lizards, and can 

 therefore prove nothing with regard to the senses of the insects them- 

 selves. But, in a few cases, the disguise is adopted for the sake of 

 deceiving other insects ; and the closeness of the resemblance may be 

 accepted as good evidence of acute vision in the class so mimicked. 

 Thus, several species of flies live as social parasites among the hives 

 or nests of bees. These flies have acquired belts of color and patches 

 of hair, closely imitating the hosts whose honey they steal ; while 

 their larvae have even the ingratitude to devour the larvae of the bees 

 themselves. Of course, any fly who entered a bee-hive could only 

 escape detection and condign punishment at the hands — or rather at 

 the stings — of its inhabitants, provided it looked so like the household- 

 ers as to be mistaken by them for one of the community. So any fly 

 which showed at first any resemblance to a bee would for a while be 

 enabled to rob with impunity : but, as time went on, the bees would 

 begin to perceive the true nature of the intruders, and would kill all 

 those which could be readily distinguished. Thus, only the most bee- 

 like flies would finally survive ; and the extent to which the mimicry 

 was can-ied would be a rough test of the perceptive powers of the 

 bees. Now, in these particular cases, the resemblance is so close that 

 it would take in, not only an unpracticed human observer, but even 

 for a moment the entomologist himself. Similar instances occur 

 among Mantidm and crickets. 



And now let us apply these facts to the consideration of the prob- 

 lem before us. If those insects which especially haunt flowers are 

 likely to have so acquired a color-sense and a taste for colors, and 

 if they are capable of observing minute markings, bands, or eye-like 

 spots, then we might naturally infer that they would exhibit a pref- 

 erence for the most beautifully colored and variously ornamented of 

 their own mates. Such a preference, long continued and handed down 

 to after-generations, would finally result in the development of very 

 beautiful and varied colors among the flower-haunting species. We 

 might expect, therefore, to find the most exquisite insects among those 

 races which are most fully adapted to a diet of honey and pollen ; and 

 such I believe to be actually the case. 



