14 Trans. Acad. Sci. of St. Louis 



them to reverse their lifelong habit, and avoid the dark 

 instead. This he does by teaching them to avoid certain 

 dark places because of disagreeable experiences asso- 

 ciated with them. The disagreeable experiences were 

 slight electric shocks from an instrument contrived by 

 him. By means of this precise apparatus, he finds that 

 male roaches learn more quickly than the females, and the 

 young ones are more apt than adults. 



Up to a short time ago, most naturalists believed that 

 insects can hear, not because it has been experimentally 

 demonstrated, but for morphological reasons, and be- 

 cause many kinds of insects can produce sounds; they 

 believed that insects would not be endowed with the 

 power of producing sounds unless other members of the 

 species could hear them. In a joint paper by Dr. Turner 

 and Mr. Ernst Schwarz, it was experimentally proven 

 that the Catocalas not only hear sounds, but that they 

 can hear sounds of certain pitch, as the authors demon- 

 strated by use of an organ pipe and Galton whistle. 

 Moreover, it was discovered that a species which re- 

 sponds only to a high pitch on the Galton whistle can be 

 taught to respond to low tones also when low tones are 

 of life significance, or in the popular language, when 

 they mean danger. 



And so on throughout his work, such alluring titles 

 appear as "Behavior of a Parasitic Bee," ''Do Ants 

 Form Practical Judgment?" ''Psychological Notes on 

 the Gallery Spider," "Habits of Mound-Building Ants," 

 "Hunting Habits of an American Ammophila," "An 

 Orphan Colony of Polistes pallipes," "The Reactions of 

 the Mason Wasp," through a list of fifty-odd titles that 

 came from his pen. 



Nature lovers and scientists cannot but feel grateful 

 for Dr. Turner's admirable contributions. In making 



