1974] 
W ussow et al. — Sounds and Motions of Insects 
213 
PI. 1. A portion of a stridulation (chirp) by Chortophaga viridifasciata, 
showing a pulse of sound in five photographs of consecutive fields (a-e). 
The male which is chirping is outlined in (a), (b) and (c) show the right 
femur blurred as it makes the downward stroke (left femur is missing). 
The two vertical black lines drawn on the trace in (d) bracket the portion 
of the oscillotrace which was scanned at the time the leg was moving in 
this field. To the right of the lines is the base of a trace which really was 
much higher, but its peaks will not be scanned until the next field (e). 
The image persistence is due to retention by the video-camera pick-up tube 
and is about equal to one field ( = 16 msec). The image in (f) is the 
result of triggering and synchronizing the CRT sweep with the “front 
porch” of the vertical field (set up as in Fig. 1). The field is identical to 
(e), but only the most intense peaks were registered. (See text, sect. 8) 
