206 ORGANISMS ILLUSTRATING BIOLOGICAL PRINCIPLES 



-crystalline lens 



used as a single eye, in conjunction with the several hundred others in 

 the compound eye. Such eyes are not very efficient. It is probable 



that they do not have any sharp vision 

 for distant objects and not very clear 

 vision for near objects. Bees have 

 been conditioned to visit boxes of 

 different-colored flowers in order to get 

 honey, but recent experiments by Lutz 

 and others indicate that they are 

 guided to flowers by odor rather than 

 by color. 



Bees also have a tactile sense which 

 comes through tactile hairs on various 



oCistol retir?alar nicclexcs P^rts of the body, these hairs being 



most numerous on the antennae. 



-Cr/stalline cone 



.outer piginent. Cell 



jcorneal pignQenL cell 

 -T-hctbcCom 



.i_retinalcti-- cell 



-Outer pigment/ oall 



The Thorax and Its Appendages 



The entire body of the bee is covered 

 with hairs, which indirectly play an 

 important part in pollen collection and 

 cross pollination, for the bee in rubbing 

 against the stamens of a flower gets a 

 good deal of pollen on the head and 

 back. The thorax is armored and thus 

 serves well its purpose as a base for 

 the attachment of legs and wings. The 

 delicate membranous wings, with their 

 ramifying veins and veinlets serving as 

 supporting structures, are outgrowths 



appendages. A wing in flight describes 

 a figure eight course, its rapid move- 

 ments being caused by four pairs of 

 muscles. 



The legs have most interesting special adaptations for the several 

 trades which the worker bee carries on. It is a typical insect leg, of 

 five divisions consisting of a heavy basal coxa, a short piece called 

 the trochanter, a long femur which with the adjoining tihia is pro- 

 vided with long hairs, and a five-jointed tarsus. The tarsus is 

 provided at the tip with a pair of strong claws, between which 



♦..ne-rve^ 



Detail of an ommatidium. 



