452 BRITISH LEPIDOPTERA. 



moth is excited or when the sexual instinct has been aroused, and that 

 the intimate connection that Swinton states to exist between the squeaking 

 and the diffusion of scent by the J" (an undoubted sexual attraction), 

 points to the cry being used in nature in order to indicate the whereabouts 

 of the caller, a very necessary detail, probably, in the case of large 

 insects which are possibly in the imaginal state never exceedingly 

 abundant, and may be more or less isolated over a large area of 

 country. The other imaginal movements said by Swinton to 

 accompany the making of the sound, such as elevating the abdomen, 

 depressing the wings, and throwing back the antennae, are all more or 

 less generally common in certain lepidoptera when under the influence of 

 sexual excitement. In spite of these more recent (and in our opinion 

 conclusive) experiments, Aigner-Abafi (lllus. Zeits.fur Ent., iv., p. 355) 

 quotes Duges view ( Physiologie comparee, ii., p 226) that the origin 

 of the sound is due to the rubbing together of the opposite halves 

 of the maxillae, and this Aigner-Abafi asserts is the true explanation. 

 He insists that the sound comes from the mouth, not in consequence 

 of air passing in and out, but by the rubbing together of the two halves 

 of the tongue which are so constructed that each has a concave and 

 a convex fold which, united, completely close the tongue, and thereby 

 made it suitable for sucking up its food ; the chitin of the groove is, 

 he avers, quite smooth and the rubbing together of the two surfaces 

 generates the sound, and this occurs only when the moth is disturbed 

 or excited. We now add Swinton's summary (evidently compiled 

 from Moseley's (Nature) article) of the literature relating to the 

 subject (Ent. Mo. Mag., xiii., p. 217). This reads as follows : 

 Reaumur says (Mem., ii., pp. 289 et sea.) the sound is produced by 

 friction of the haustellum against the palpi ; Roesel considers ( Ins.- 

 Belustigiuig, iii.,p. 16) that it is due to the friction between the abdomen 

 and thorax; Rossi (Opuscoli Scelti, v., pp. 173 <?/ seq.) to expiration 

 of air from the haustellum ; Schroter (Eer JVaturf., xxi., pp. 

 66 et seq.) to the friction of the haustellum and head ; Engrameile 

 says (Pap. d'Europe, hi., pp. 84 et seq.) that it proceeds from 

 the " spallette " ; and Lorey (Godart's Hist. JVat. des Lep., 

 hi., pp. 18-19) from expiration at the base of the abdomen; 

 Passerini ( Osservazioni sopra la S. atropos, etc., Pisa, 1828) from 

 the haustellum, caused by expiration from a suction-cavity ; 

 Rochebrune's views (Act. Soc. Linn. Bord., v., pp. 120-122) have 

 already been detailed at length ; Burmeister ( Handb. der Entomologic, 

 i., p. 514) asserts that the seat of the voice is in the head; Wagner 

 (Muller's Archiv fur Phys., iii., pp. 60-62) thinks that it is 

 due to expiration from the large vesicles at the anterior part of 

 the abdomen through the oesophagus and haustellum; Vallot and 

 Johet (E Institut, ii., p. 7) believe that it is produced by wing 

 percussion; Duges (Traite de Physiol. compa)-ee, ii., p. 226) that it 

 proceeds from the friction of the opposite edges of the two halves of 

 the haustellum, whilst Nordmann reverts to the idea {Bull. 

 Acad. St. Peters., iii., pp. 164 et seq.), that the sound is 

 due to expiration of air at the base of the abdomen. 

 Duponchel and Guerin (Ann. Soc. Ent. France, viii., pp. 

 59 et seq.) then refute Passerini, and state that the sound 

 arises from the friction of the prothorax on the scutellum, 

 while Goureau (loc. cit., vi., p. 66) asserts that it arises from 



