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 orcran. 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 attached 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 cuneiforna, stafi'-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 



r 



i 



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

 Muscidae 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 timeof 

 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_f^bvre, Ann. d. la 

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

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

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

 against the opinion oi Marcel de Serres (Ann. du 

 >Ius. XVII. p. 426), who locates this sense, with 

 the Ortlioptera, in the palpi. Equally 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 hira, 

 the numerous small fossae of these organs are cov- 

 ered internally with a delicate membrane sensible 

 to odors.* 



1 The author who has erred most widely in this 

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

 September, 1838, or in Froriep's neue Notiz. IX. 

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

 the antennae of Carabus nemoralis, Illig. an 

 auditive apparatus, composed of an Auricula, a 



Meatus auditorius externus and internus, a 

 Tympanum, and a Labijrinthus, 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 (Annal. 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 tlie Entom. Soc. 

 II. p. 229) and Goureau (Ann. d. I. 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 (JViegmann^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 i for it is 

 not at all supposable that the antennal nerve can 

 serve at the same time the function of two distinct 

 senses. 



2 This organ has been taken for a soniferous ap- 

 paratus by Latreille (Mem. du Mus. VIII. p. 123) 

 and Burmeister (Ilandb. I. p. 512). J. Mailer 

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

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

 who fortunately conceived that with Gryllus hiero- 

 glypkus, 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 {fViegmannU 

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



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

 fiir Zool., Zoot., und PalSon.ol. von V Alton und 

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

 likewise advocates the auditory function of the 

 antennae. But Burmeister and Erichson differ 



somewhat in their statements upon the intimate 

 auditory structure of these organs, and, therefore, 

 as to the exact mode by which audition occurs. — 

 Eo. 



