286 C. H. TURNER AND E. SCHWARZ. 



but, in some cases, the air current was allowed to strike the moth. 

 The results of those experiments are recorded in tables I .-II I. 



On the twelfth of June the three specimens, which, up to that 

 time, had been confined in separate rooms, were marked and 

 placed in the same room. At nine A.M. that day, on the first 

 sound of the whistle, they all flew, one after another, as though 

 the flight of the first had evoked the flight of the others. At 

 ten o'clock, the whistling caused two to fly and the other to 

 quiver. The one that quivered was about ten feet away. On 

 whistling again all flew. At six P.M. the whistling caused all to fly. 



To our way of thinking this series of experiments is very in- 

 structive. That each of these three specimens responded to the 

 whistle on the twelfth of June is unequivocal; that they usually 

 responded to the whistle by either flying or by quivering is also 

 evident; but, it is equally certain that two out of the three speci- 

 mens did not respond to the whistle at all the first time it was 

 sounded and that the third specimen responded in a feeble man- 

 ner. When the moths did not respond to the blowing of the 

 whistle at the beginning of the experiment, the current of air 

 produced by w r histling was allowed to strike the moth; imme- 

 diately it flew, and thereafter it would usually fly when the 

 whistle was sounded. There were some exceptions to this; but, 

 in the main it was true. This seems a hint that the moth responds 

 to sounds that have a life significance. 



FIELD EXPERIMENTS. 



These experiments were conducted in a small stretch of woods 

 at Meramec Highlands, near St. Louis, Mo. Previous experience 

 had taught us that these insects would not respond to loud sounds 

 of low pitch. For that reason we used as the sound producing 

 instrument a Galton whistle set to give a high shrill note. One 

 of us would stand where the moth could be observed; but far 

 enough away not to disturb it. Experience had taught us what 

 would be a safe distance. The other, whistle in hand, would 

 approach the tree on the opposite side to that on which the moth 

 was resting. When this experimenter was near to the tree the 

 whistle was held at about the level of the moth and sounded one 

 or more times. In such a position it was absolutely impossible 

 for the moth to see either the whistle or the experimenter. The 



