
Figure 5.--Two-transistor control relay, utilizing an 
A 15-M selenium photovoltaic cell for the light control. 
www RECORDER 

6 
Figure 6.--Micro-ducer pressure-sensitive transducer 
mounted between a corn earworm moth's wings to record force 
of wing beat above back. The 100,000-ohm, variable rheostat 
allows for calibration of range extremes on the recorder. 
Pa oe 
