Bioacoustics of Monseremus appendiculatus

Description of the males. Habitus and colouration similar to female described in Ingrisch (2018) ( Fig. 4A ). Four stridulatory files on first and second abdominal tergites, two on each tergite ( Fig. 4B ): Anterior file on first tergite short with 5 peg-like teeth (n = 2♂ ). Second file, also on first tergite, longer, more than twice the length of anterior file, slightly curved, with 12–13 peg-like teeth (n = 2♂ ). Third file on second tergite angularly curved, with 15–17 peg-like teeth (n = 2♂ ); teeth more densely packed than second file; posterior file on second tergite nearly straight, with 16–17 peg-like teeth (n = 2♂ ). Second and posterior files of subequal length. Eighth abdominal tergite enlarged, longer than other tergites ( Figs 4C, 4D ). Ninth abdominal tergite forming a hood ( Fig. 4D ). Tenth abdominal tergite with two processes in the middle; each process broadest at the base, triangular, pointing ventrally and produce into a sclerotized and obtuse apex ( Fig. 2C ); the process not touching each other at the apex ( Fig. 2C ). Epiproct concealed beneath tenth abdominal tergite ( Fig. 2C ). Cercus long and slender, cylindrical and setose, curved internally at the posterior end, with acute apex ( Fig. 2C ). Subgenital plate circa 1.7 times wider than long; anterior margin broadly concave; lateral margin straight, with some setae; posterior margin slightly emarginated in the middle, laterally forming a lobe where stylus is inserted ( Fig. 2C ). Stylus short and stout, setose, with obtuse apex ( Fig. 2C ). Measurements (in mm, n = 2♂ ). BL = 18.6–21.3, HL = 2.8, PL = 5.0–5.3, PW = 5.9–6.6, HFL = 13.1–15.0, HTL = 12.5–14.1.