282 C. H. TURNER AND E. SCHWARZ. 



moths mutually heard. In face of the well known fact that the 

 sense of smell is well developed in butterflies and moths, the 

 evidence just cited does not appear to be conclusive. 



Is it possible for anyone to read the above historical resume 

 and not be convinced that there is need for much exact experi- 

 mentation upon the auditory powers of insects? Evidently the 

 last word has not been spoken. 



DESCRIPTION AND DISCUSSION OF EXPERIMENTS. 



Reading Stephan's ('12) recent articles on sound producing 

 butterflies and moths induced in us the same thought that 

 influenced the opinions of many of the early investigators; 

 namely, animals that produce sounds as a part of their normal 

 behavior can probably hear. We decided to make some crucial 

 experiments. The Catocala moths were selected for the following 

 reasons: (i) one of us is so well acquainted with the taxonomy 

 of the group that it is easy to identify species afield ; (2) the habit 

 these moths have of resting during the day on some tree trunk 

 and, when disturbed, flying to a nearby tree trunk renders them 

 ideal material for field experiments. 



PRELIMINARY OBSERVATIONS. 



Observations afield taught us that there are certain sounds to 

 which these moths do not respond. A favorite haunt of the 

 Catocala moths of this vicinity is a small stretch of wood through 

 which a railroad passes. Moths resting on trees near the tract 

 are not disturbed by the whistle, rumble and roar of passing 

 trains. . Near that same place there is a pleasure garden in which 

 the sounds of 'a noisy piano are often heard. No responses to 

 the strains of the piano were noticed. 



These observations are in harmony N with those of Heinrich 

 ('09), Hamann ('09) and Richter ('09, '10). 



INDOOR EXPERIMENTS ON CATOCALA UNIJUGA. 

 Three specimens freshly hatched from pupae were the subjects 

 of these experiments. Each was kept in a separate room. 

 Three times a day, for four days, the auditory powers of these 

 moths was tested by whistling in a high key. Occasionally the 

 moth was shielded from the draft of air caused by whistling; 



