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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8l 



Fig. 13. — So-called auditory organs of Lepidoptera. A, Diagram from longi- 

 tudinal section through portions of thorax and abdomen of a noctuid moth, 

 showing following parts of tympanic organ: Gu Tympanic pit at whose base 

 is found the drum head (T) and G2, tympanic cavity with drum head (GT). 

 The two tympanic cavities are very deep, dorsolateral invaginations of the in- 

 tegument which touch one another at the median line where they form a com- 

 mon division wall (MS). In Catocala they do not touch one another. Tb, 

 Tympanic chamber; A'^, tympanic nerve; Ch, chordotonal bundle; L, ligament 

 of same; Td, tympanic cover; and Lni, chitinous lamella, separating the true 

 drum head (T) from the other drum head (GT) and serving for the insertion 

 of the chordotonal bundle (after Egger (17)). B, Chordotonal bundle of a 

 notodontid (Phalcra buccphala L.), showing drum head (T), ligament (L) of 

 chordotonal bundle, tympanic nerve (A''), sense cell (Sc), sense rod or " Stift " 

 (Sr), and cap cell (Cc), (after Egger (15))- C, Portion of drawing from 

 longitudinal section through base of front wing of Lycacna icarus, showing 

 chordotonal organ (Ch) and " Sinncskuppeln " (P) or olfactory pores. D, 

 Single chordotonal element from front wing of Chimabacchc fac/, showing sense 

 cell (Sc), vacuole (Va), enveloping cell (Ec), axial fiber (-^.r), sense rod 

 (Sr), and cap cell (Cc). C and D after Vogel (89). 



