168 THE SENSE ORGANS AND REFLEX BEHAVIOUR 



light rays, are the only reflex responses of insects that have been 

 found to lend themselves to practical utilisation to any consider- 

 able extent. It has been shown that chemotropic responses afford 

 a highly promising field for exploration, while, on the other hand, 

 the phototropic responses of insects have so far yielded less 

 encouraging results. It is unlikely that material advances will 

 come from the application of existing methods of utilising these, 

 or other phases of insect behaviour, until much more thorough 

 exploration of their fundamental aspects has been undertaken. 

 Up to the present so many of the experiments have neglected to 

 take into account the numerous interacting factors involved. 

 Until their influence can be adequately evaluated the empirical 

 methods, so far practised, are scarcely amenable to material 

 improvement. Properly controlled experiments, using the most 

 scientific equipment available, afford the only sure method of 

 obtaining knowledge capable of being turned to practical 

 advantage. 



Literature 



A. The General Subject 



Berlese, 1909. " Gli Insetti." Milan. 



VON Frisch, 1924. " Sinnesphysiologie und ' Sprache ' der Bienen." Berlin. 



LoEB, 1918. " Forced Movements, Tropisms and Animal Conduct." London 



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 McIndoo, 1926. Journ. Agric. Res., XXXIIL, 1095. 

 1929. Smithsonian Misc. Coll., LXXXL, No. 10. 

 SiHLER, 1924. Zool. Jahrb., Abt. Anat. Ont., XLV., 519. 

 Snodgrass, 1926. Smithsonian Misc. Coll., LXXVIL, No. 8. 

 VoGEL, 1923. Zeits. wiss. Zool., CXX., 281. 

 Wheeler, 1928. " The Social Insects." London. 



B. The Eyes and Light Perception 



Bertholf, 1931. Journ. Agric. Res., XLIL, 379 ; XLIIL, 703. 



1932. Zeits. vergl. Physiol,, XVIIL, 32. 

 BozLER, 1925. Ibid., IIL, 145. 

 Buddenbrock, 1931. Ibid., XV., 597. 



BuDDENBROCK and ScHULTZ, 1933. Zool. Jahrb., Abt. Physiol., LIL, 513. 



Ellsworth, 1933. Aim. Ent. Soc. Am., XXVL, 203. 



Eltringham, 1919. Trans. Ent. Soc, 1. 



Friedrich, 1931. Internat. Ent. Zeits., XXV., 326. 



VON Frisch, 1914. Zool. Jahrb., Abt. Physiol., XXXV., 1. 



Gaffron, 1934. Zeits. vergl. Physiol., XX. 



Glaser, 1925. Pstjche, XXXIL, 285. 



Hertz, 1931. Zeits. vergl. Physiol., XIV., 629. 



1933. Biol. Zentralb., LIIL, 10. 



1934. Zeits. vergl. Physiol., XXL, 579. 



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