302 
Psyche 
[September 
It is interesting, then, how visual-acoustical signals have diversified 
within this species. In A. conspersa , the basic single-pulsed sound is 
similar in the chirp, rasp, buzz, squeal. Each of these signals differs 
primarily from the others in pulse duration, intensity, and pulse rate 
frequency. The chirp is intense, variably spaced, multiple and with 
a high pulse rate frequency. The rasp is intermediate in pulse rate 
frequency and of lower amplitude. The squeal is a rapidly delivered 
short train of chirps, with a, high degree of frequency variation. It 
is of further significance that the unitary chirp, precopulatory burst 
of chirps, flutter-rasp, flight crepitation, and buzz signals differ in 
pulse rate frequency in an ascending scale of i, io, 20, 45, and 
100/second respectively, which indirectly indicates a Weber-Fechner- 
like discrimination of pulse rate frequency. If one invokes an ascend- 
ing scale of specific action potential (ethologists’ SAP) which is 
excited by this series of frequencies to produce specific behavioral 
patterns, then such a relationship between perception and specific 
choice of behavior pattern can be postulated which could be inde- 
pendent of the intensity of the specific stimulus. Differences in 
intensity of each stimulus could in turn result in complex scototaxis 
and phonotaxis in a manner similar to that shown in Ephippiger 
spp. (Dumortier, 1963). We are currently studying this problem 
in respect to the male-male interactions in several species of Arphia. 
ACKNOWLEDGEMENTS 
We are grateful for the aid of David Werner, Ruth Lewert, 
Allen Berlind, Gerald Mussgnug, Joyce Redemske, Melvin Shem- 
luck, and Marianne Niedzlek, our assistants and students for at 
least one of the years of study. We thank Dr. Walter Roberts, 
Director of the National Center for Atmospheric Research and Dr. 
James Deardorff for enabling us to study the Table Mesa popula- 
tion during May and June of 1964. We also are grateful for the aid 
and encouragement of Professor Robert Enders, Director of the 
Rocky Mountain Biological Laboratories during most of the period 
of this research, and Professor John Corliss, Head of the Department 
of Biological Sciences, University of Illinois at Chicago Circle. We 
appreciate the helpful suggestions and encouragement of Dr. Richard 
D. Alexander, University of Michigan, who made, several years ago, 
sonograms of signals we recorded very early in the study. 
SUMMARY 
Arphia conspersa , an oedipodine grasshopper, is widely distributed 
