INSECT MUSICIANS — SNODGRASS 



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at its outer end with the hypodermis or cellular layer of the body 

 wall and at its inner end with a nerve (Nv) from one of the ventral 

 ganglia. The organ consists of a main body and a slender branch. 

 The former is attached by a wide base to a hollow peglike ingrowth 

 of the tympanum (Pg), formed by a pit on the external surface 



Nu 



Fig. 34. — Details of sensory structures of the grasshopper's ear. A, the tympanal sense 

 body or Mflller's organ (SB) of Dissosteira Carolina, attached to the peg (Pg) and the 

 pear-shaped thickening (P) of the tympanum, d, v, thickenings of the tympanum 

 forming dorsal and ventral arms supporting the peg (Pg). B, the same more enlarged 

 and showing Internal structure of the sense body, which has two divisions, the larger 

 attached to the peg (Pg), the other attached to the pear-shaped support (P). CCl, 

 cap cells ; d, dorsal arm of peg ; Nu, nucleus of enclosing membrane ; Av, nerve ; P, 

 pear-shaped support of branch of sense body ; Pg, peg supporting main part of sense 

 body ; SCls, sense cells ; Sco, scolopala ; v, ventral arm of peg. C, a scolopala and its 

 axial fiber (F), greatly enlarged. D, a single series of cells from the sense body of 

 Acridium aegytpticum (from Schwabe), consisting of a cap cell (CCl), an enveloping 

 cell (ECl), and a sense cell (Scl). The enveloping cell contains a scolopala (Sco) and 

 a vacuole (Vac), both traversed by a fiber (F) from the sense cell. E, details of an 

 enclosing cell and scolopala (from Schwabe). P, surface view of a scolopala, greatly 

 magnified; G, optical section of the same (from Schwabe). 



(A,Pt). The peg is supported by two arms or thickenings of the 

 tympanum (d, v) that make a wide angle with each other. The 

 branch of the sense body is attached to a pear-shaped thickening (P) 

 of the tympanum. 



The sense body itself consists of a mass of cells arranged in two 

 groups (fig. 34, B), one forming the main part of the body connected 

 with the peg (P{/), and the other prolonged into the branch sup- 



