1975] 
Willey — Sound Production in Arphia 
331 
Fig. 7. Audiospectrograms of representative unitary chirps by A. sul- 
phured and the respective oscillograms (inserts), (a) Chirp recorded under 
ptenocinematographic conditions in water-cooled cage, audiometric room, 
35°C, Sennheiser 404 microphone at 2 cm with 6 m extension cord, (b) 
Chirp recorded under usual conditions of laboratory analysis (microphone 
10 cm from insect, 33 °C, 20 X 30 cm wire cage in quiet room). Protocol: 
Audiospectrograms — 0 db input and output levels, 38.1 cm/sec; record 
level +2 to 3 VU, 0.8 sec per revolution; print level -10 VU, filter band 
width 600 Hz. Oscillograms — vertical — 10 V per division, horizontal = 
1 msec. Arrows point to the 10 msec portions of the sonagram from which 
each oscillogram was derived. 
into antiphase, cancelling each other. The sonagrams show that the 
greatest amplitude (darkest and thickest portion of the trace) always 
falls in frequency, and the oscillotrace in Figs. 22 and 31 shows this. 
The faintest portions of the downstroke sonagram are not clear 
because the period of antiphase is only fractions of a millisecond 
(Figs. 14, 26, and perhaps 32). The frequencies are variously 
modulated in other frames between Figs. 13 and 39. The oscillotrace 
in Figs. 10 to 13 definitely is the result of the movement of the left 
femur only. However there is some modulation irregularity in the 
trace from Fig. 39 to Fig. 43, which could be the result of continued 
unobserved motion of the left femur or some other sound. Figure 43 
is typical of the background noise, whereas Fig. 8 is typical of the 
40 frames during the upstroke, i.e., wavering non-regular traces of 
low frequency and amplitude. 
