At least seven locations have been proposed for the sonic mechanism of Hamadryas butterflies, which has not been identified to date. Using light microscopy, five species of Hamadryas (including a "mute" population) were compared with Siproeta stelenes, Anartia fatima and Ectima thecla, which do not emit audible sound. Three macrostructures were found exclusively in Hamadryas: the abdominal rami, and in the forewings, a hemispheric membrane in the costal cell and the swollen base of the

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... vein. Only the third appears to be related to sound emission (possibly, percussion by clapping the wings). Thus, the fore wings appear to be the most feasible location for the sound emission mechanism in Hamadryas.