FIGURES 55‒57. Gloora alba comb. nov., scanning electron micrographs of a female tymbal organ after brushing off the overlying scales (55, 56) and a spectrogram (57) showing a modulation cycle with ten clicks in the active and passive modulation half cycle. The acoustic structure of sounds produced in response to manual stimulation meets the general assumptions on arctiine sound production (Blest et al. 1963; Fullard & Fenton 1977) but differ insofar as the passive modulation half cycles are in comparison to the respective active cycles less emphasized, i.e. with lower overall amplitude of the click trains. Courtesy of Philipp Klein, FZE, Freiburg (cf. Klein et al. 2018). Scale bars: 100 µm / 5 msec.