170 EVENINGS AT THE MICROSCOPE. 



are called, in many other insects, though they are not 

 so universally present as the compound eyes. On the 

 forehead of the Honey-bee they are well seen, as three 

 black shining globules, placed, as in the Dragon-fly, in a 

 triangle. 



It is reasonable to presume that some difference, im- 

 portant to the insect, exists between the perceptions 

 obtained by means of the simple, and those obtained by 

 means of the compound, eyes ; but what is the nature of 

 the difference is certainly not known, and probably could 

 not be imagined by us, who know only one kind of 

 vision. 



