416 



THE INSECTA. 



§ 335. 



§ 335. 



There is the same uncertainty concerning the organs of Audition. 

 Experience having long shown that most Insecta perceive sounds, this sense 

 has been located sometimes in this, and sometimes in that organ. But in 

 these opinions, it often seems to have been forgotten or unthought of, that 

 there can be no auditive organ, without a special auditive nerve which 

 connects directly with an acoustic apparatus capable of receiving, conduct- 

 ing, and concentrating the sonorous undulations. "> 



Certain Orthoptera are the only Insecta with which there has been dis- 

 covered, in these later times, a single organ having the conditions essential 

 to an auditive apparatus. This organ consists, with the Acrididae, of two 

 fossae or conchs, surrounded by a projecting horny ring, and at the base of 

 which is stretched a membrane resembling a Tympanum. On the internal 

 surface of this membrane, are two horny processes to which is attiiched an 

 extremely delicate vesicle filled with a transparent fluid and representing 

 a membranous labyrinth. This vesicle is in connection with an auditory 

 nerve which arises from the third thoracic ganglion, forms a ganglion upon 

 the tympanum, and terminates in the immediate neighborhood of the 

 labyrinth by a collection of cuneiform, staff'-like bodies with very finely- 

 pointed extremities (primitive nerve-fibres ?), which are surrounded by 

 loosely-aggregated, ganglionic globules.'-* 



The Locustidae and Achetidae have a similar organ, situated in the 



136, Taf. VII r. fig. 5, 6), the olfactory organ of the 

 Musciilae is a double, oblong fossa, situated under 

 the antennae, and covered by a plicated membrane 

 formed by the cutaneous envelope, which is other- 

 wheres solid and dry. Until lately, from the time of 

 Reaumur, the sense of smell has been located in 

 the antennae, although they present no trace of a 

 humid surface, and have none of the anatomical 

 and physiological conditions requisite for being the 

 seat of this function. See Le/ebvre, Ann. d. la 

 Soc. entom. d. France, VII. p. 395, or Ann. 

 d. Sc. Nat. XI. 1839, p. 191 ; and Küster, Isis, 

 1844, p. 647. The same objections might be raised 

 against the opinion of Marcel de Serres (Ann. du 

 Mus. XVII. p. 426), who locates this sense, with 

 the Orthoptera, in the palpi. Ecjually groundless 

 appears the view of Baster quoted by Straus 

 (Consider. &c. p. 420), that this sense is seated in 

 the stigmata of the tracheae. Treviranus seeks to 

 avoid the difficulty in supposing that the entire 

 buccal cavity, which is humid, can receive odorous 

 impressions. Erichson (Diss, de fabr. et usu an- 

 tenn. in Insect., Berlin, 1847) has recently appeared 

 anew in favor of the antennae. According to him, 

 the numerous small fossae of these organs are cov- 

 ered internally with a delicate membrane sensible 

 U> odors.* 



I The author who has erred most widely in this 

 respect, is L. fV. Clarke (Magaz. of Nat. Hist. 

 September, 183S, or in Frorie/)'.i neue Notiz. I.X. 

 p. 4, fig. 12, a-n), who has described at the base of 

 the antennae of Carahus nemoralix, Ulig. an 

 auditive apparatus, composed of an Auricula, a 



Meatus aiiditorius externus and internus, a 

 Tympanum, and a Labyrinthus, of all of which. 

 there is not the least trace. The two white convex 

 spots at the base of the antennae of Blatta orien- 

 talis, and which Treviranus (.\nnal. d. Wetter- 

 auisch. Gesellsch. f. d. gesammte Naturkunde, I. 

 lift. 2, p. 169, Taf. V. fig. 1-3) has described as- 

 auditory organs, are, as Burmeister has correctly 

 stated (Handb. II. p. 469), only rudimentary acces- 

 sory eyes. Newport (Trans, of the Entom. Soc. 

 II. p. 229) and Goureau (Ann. d. 1. Soc. ent. X. p. 

 10) think that the antennae serve both as tactile 

 and as auditory organs. But this view is inadmis- 

 sible, as Erichson (fVie^manji's Arch. 1839, II. 

 p. 285) has already stated, except in the sense that- 

 the antennae, like all solid bodies, may conduct 

 sonorous vibrations of the air ; but, even admitting 

 this view, where is the auditory nerve > for it is 

 not at all supposable that the antennal nerve caa 

 serve at the same time the function of two distinct 

 senses. 



2 This org.nn has been taken for a soniferous ap- 

 paratus by Latrrillr (Mem. du Mus. VIII. p. 12.3)' 

 and Burmristcr (llaiidb. I. p. 512). J. Müller 

 (Zur vergleich. Physiol, d. Gesichtssinn, p. 439, and 

 Nov. Act. Nat. Ciir. XIV. Tab. IX.) was the first 

 who fortunately conceived that with Gryllus hiero- 

 ß:lypkus, this was an auditory organ. He gave, 

 however, this interpretation only as hypothetical ;, 

 but I have placed it beyond doubt by careful 

 researches made on Gomphoceros, Oedipoda, Po- 

 disma, Caloptenus and Truxalis {IViegmann's 

 Arch. 1844, 1. p. 56, Taf. I. fig. 1-7). 



* [ § 334, note 1.] See also Burmeister (Zeit. 

 für Zool., Zoot., und PalSontol. von D'' Alton und 

 Hurmeisler, No. 5, p. 49, Taf. I. fig. 25-29), who 

 likewise advocates the auditory function of the 

 antennae. But Burmeister and Erichson dilVer 



somewhat in their statements upon the intimate 

 auditory structure of these organs, and, therefore, 

 as to the exact mode by which audition occurs.— 

 Ed. 



