14 



THE PHYSIOLOGY OF INSECT SENSES 



Fig. 7. Examples of Type II neurons. A and B. Subepidermal nerve plexus 

 in the larva of Melolontha. (Redrawn from Zawarzin, 1912.) 



the path from the primary neuron to the central nervous system is a 

 direct one. According to Snodgrass (1935) there are no cells in 

 sensory nerves, and Wigglesworth (1953) is of the opinion that the 

 cells seen there are actually neurilemma cells. 



Morphologically there are two broad categories of sense cells: 

 those whose dendrites are nearly always associated with the cuticle or 

 its invaginations (apodemes, tracheae, and cuticle of preoral and oral 

 cavities) (Type I) (Fig. 5) ; multipolar neurons never associated with 



