412 INTRODUCTION TO ZOOLOGY chap. 



wide and protrudes her tongue, regurgitating food from her 

 crop into her mouth ; the hungry one then excitedly 

 presses up to her and begins licking up the food off her 

 friend's tongue, all the while continuing to stroke her, 

 lifting her front legs and holding on to those of her 

 companion which are also raised, so that they stand in the 

 position shown in Fig. 313. This feeding may continue for 

 as long as five minutes, during which time other hungry 

 workers may come up and try to get a turn. The moment 

 the first has had her fill, one of these rushes in and attempts to 

 get a second meal from the forager, who sometimes, however, 

 refuses it, shutting her mandibles and running off. 



As soon as they have fed, the workers busy themselves 

 with cleaning their antennae, passing the front leg right over 

 them, and then drawing them through the "strigil" (page 

 405). They are very dainty in their toilet, and keep their 

 bodies perfectly free from dirt by regular lickings and 

 brushings. 



During the coldest months of the year the ants 



Winter retreat further underground, only occupying the 



lowest parts of their nests ; there they remain in 



a semi-torpid condition without feeding until the spring, a 



large number of the workers always clustering round the 



queen as if to keep her warm. 



The Senses of Ants} 



Though ants have two complex compound eyes 

 of Sieht* and often three simple ones as well, their power of 

 sight is probably very limited, for their eyes do 

 not seem adapted for producing clear images of external objects. 

 The compound eyes, according to Exner's^ view, form a 

 single, upright, much-reduced image of an object, and the 

 more convex the surface of the eye, and the greater the 

 number of facets in it, the clearer is this image ; if this is 

 so, the specially large convex eyes of the male must be 

 particularly valuable as enabling him clearly to see the flying 

 queens. 



The simple eyes, or ocelli, on the other hand, probably 



^ See The Senses of Insects, by Auguste Forel (published in Englisli, 1908). 

 ^ Die Physiologie der facettirten Augen von Krebsen und Insecteii (1891). 



