The Nervous System and the Senses 169 



color. It is asserted that ants do not perceive red light 

 and the same statement is made concerning bees, but 

 this is incorrect for bees. It is also sometimes said that in- 

 sects perceive some of the ultraviolet rays, beyond the range 

 of human vision. The color preferences of bees have also 

 been observed, it often being stated that they prefer blue. 

 It seems certain that bees do not see objects distinctly 

 and their vision is clearly far less acute than that of wasps 

 and some other insects. Perhaps they do not perceive the 

 form of objects at all. The relative intensity of light is 

 probably an important part of their vision. When it is re- 

 called that the hairs (p. 104) cover many facets of the com- 

 pound eye, especially in younger bees, and that the structure 

 of the eyes does not suggest a high degree of efficiency in 

 vision, it becomes a matter of wonder that bees are helped 

 by vision as much as appears to be the case. 



Smell. 



It is commonly believed that bees possess an acute sense 

 of smell, and this belief is borne out by experiments on this 

 subject. With the exception of qualifying statements by 

 Lubbock l and Forel, this is usually conceded. The location 

 of the olfactory organs is a matter of much less unanimity 

 of opinion. Mclndoo 2 has recently performed a valuable 

 service in gathering together the literature on the olfactory 

 organs in insects and it is necessary only to give a list of the 

 organs which are supposed to carry the olfactory organs to 

 show the confusion which has existed. These sense organs 

 have been located by various authors on the following struc- 

 tures : (1) the spiracles, (2) organs close to the spiracles, 

 (3) glands of head and thorax, (4) oesophagus, (5) " internal 

 superior surface," (6) folded skin beneath antennae, (7) 

 rhinarium, (8) plate between eyes and beneath antenna?, 



1 Lubbock, Sir John, 1899. The senses, instincts and intelligence of 

 animals. Internat. Sc. Ser. Lojidon., vol. 65. 



2 Mclndoo, N. E., 1914. The olfactory sense of insects. Smithsonian 

 misc. col. LXIII, no. 9, 63 pp. 



