114 



CHORDOTONAL ORGAN OF GNAT-LARVA. 



swells into a little triangular ganglion at g) from g 

 the auditory organ runs straight to the skin at e, 

 and contains two or three auditory rods (not, how- 

 ever, shown in the figure) at the point Chs ; in the 

 opposite direction, a fine ligament passes from g to the 



Fig. T2. — Right half of eighth segment of the b:)dy of the larva of a gnat (Corethra 

 plumicornis) ; after Graber. EG. Ganglia; JV, nerve; g, auditory ganglion; 

 pb, auditory ligament ; C7is, auditory rods; a, auditory nerve; e, attachment ot 

 auditory organ to the skin ; b, attachment of auditory ligament to the skin ; 

 hn, hn', termination of skin-nerve; tb, plumose tactile hair; h, simple hairj 

 tg, ganglion of tactile hair; Im, longitudinal muscle. 



skin at h. Hence the organ ge is suspended in a 

 certain state of tension, and is favourably situated to 

 receive even very fine vibrations.* 



There are, as we have seen, a large number of 

 observations which point to the antennsB as organs of 

 hearing, and many more might have been given. 

 When we come to consider, however, the anatomical 

 provision which renders the perception of sound 



* Similar organs occur in other insects, as, for instance, in Ptychoptera. 



