196 FLASHLIGHTS ON NATURE 



a troop of ants trying to drag a de'ad insect over 

 a gravel path, and surmounting all obstacles with 

 clumsy ingenuity. Ants, in short, are built for 

 navvies ; they are insect engineers, and they have 

 acquired a form exactly adapted to their peculiar 

 habits. 



But why are the worker ants so nearly blind ? 

 That must surely be a disadvantage to them. 



Not a bit of it. 

 Ants work mainly 

 in dark under- 

 ground passages, 

 where the sense 

 of sight would be 

 of little use ; and, 

 moreover, like all 

 hunting animals, 

 they find smell 

 more important as 

 an indicator of 



NO. 8. HEAD OF GARDEN ANT, WITH EYES, food in the Open 

 ANTENNA, JAWS, AND FEELERS. than V i S i On . The 



hound does not 



look for the fox he sniffs and scents him. Now, 

 whenever any sense is relatively unimportant, an 

 economy may be effected by suppressing or cur- 

 tailing it ; the material that would otherwise go to 

 making and repairing its organ is more profitably 

 employed on some better work elsewhere. Ants 

 are obviously descendants of flying ancestors, none 

 of which were workers ; and the flying males and 

 females possess to this day the organs of sight 



