634 THE SENSES AND SENSORY ORGANS. 
The sete are on an average o'r mm. in length, and each 
apparently receives a process from one of the subjacent 
ganglion cells. A layer of small cells lies immediately beneath 
the cuticle, and these apparently send processes into the bases 
of the sete. The deeply-seated position of this organ in a small 
pouch on either side of the front of the prosternum renders it 
Fic. 85.—A highly magnified section of a part of the prosternal organ; g, ganglion 
cells; 4, hypodermal cells ; 7, nerve; s, transparent sete. 
most improbable that it is a tactile organ, and its sete present 
a similarity to the large olfactory setee in the sacculi on the 
antenna, which is very striking, although they are twice as long. 
Further observations are needed to throw light upon the nature 
of this most puzzling organ. 
