This enigmatic structure is similar in position to the aural orifice of Locustidae (see Fig. 101); but it is closed by a transparent membrane, whereas the ear orifice of Locustidae is, as we shall subsequently see, quite open.
Rev. biol. Nord France, vii. 1894, p. 111.
Ann. Nat. Hist. Decr. 6th, ser. x. 1892, p. 433.
Prod. Orth. europ. 1882, p. 27, and Rev. Syst. Orthopt. 1892, p. 15. Unfortunately de Saussure adopts a different nomenclature; we have preferred Brunner's as being more simple.
Ann. Sci. Nat. Zool. ser. 5, x. 1868, p. 161.