CHORDOTONAL SENSILL^ 



147 



wired to a loudspeaker. His observations are to be regarded as 

 giving further evidence supporting Crozier's theory of geotropic 



Fig. 62. Third leg of first instar nymph of Pediculus. c, mono- 

 scolopal chordotonal organ ; cl, claw ; e, extensor muscle of 

 tibia ; /, flexor muscle of tibia ; fc, flexor muscle of claw ; 

 fe, femur ; n, nerve of leg ; t, tarsus ; ti, tibia. (From Keilin 

 and Nuttall.) 



orientation, which involves the presence of tension receptors. So 

 far, no sensory nerve endings have been detected in insect muscle, 



