40 



THE PHYSIOLOGY OF INSECT SENSES 



Campaniform Sensilla (Compression and Stretch Receptors) 



The term sensilla campaniformia was proposed by Berlese (1909) to 

 apply to all sensilla similar to those originally described by Hicks 

 (1857). These organs consist of a canal in the cuticle covered by a 

 domed cap and innervated by a single bipolar neuron (Fig. 11, 30) 

 (Newton, 1931; Vogel, 1911; Sihler, 1924; Pflugstaedt, 1912; 

 Mclndoo, 1914 a, 1914 b ; Snodgrass, 1935 ; Hsu, 1938 ; Slifer, Prestage, 

 and Beams, 1959). The cap is lined with a substance that has different 

 staining properties from the rest of the cuticle. The dome may extend 

 above the general cuticular surface, be flush with it, or be recessed. The 

 distal neuronal process extends within the scolopoid sheath (Slifer 



Fig. 30. Structure of the cuticular parts of various types of campaniform 

 sensilla. A, outer lamella of dome; B, inner lamella of dome; C, cuti- 

 cular connexion of dendrite of sense cell. (Redrawn from Snodgrass, 

 1935.) 



et al, 1959) and is inserted on the underside of the cap by a highly 

 refractile body. 



These sensilla occur on practically all parts of the body. One of the 

 earliest suggestions that they are proprioceptive organs came from 

 Demoll (191 7), many of whose speculations concerning the mechanism 

 of action were given substance by the work of Pringle (1938 b). It is 

 interesting that there is no known case of these sensilla occurring on a 

 part of the cuticle free from strain. They are concentrated especially 

 where stresses are set up by muscular contractions (e.g., leg, wing, 

 haltere, ovipositor, and mandibular joints). A model has been 

 constructed by Pringle (1938 b) to explain their probable action 

 (Fig. 31). 



A thin, flat surface such as the cuticle can be subjected to bending 



