52 OLFACTORY PITS. 



the aBtenna3 and mandibular palpi of tlie crayfish 

 (Asiacics fluviatilis) but I do not find any further 

 description of them. On the other liand, in insects thev 

 play a more important part, and it will be convenient 

 to describe here very briefly the various structures 

 occurring on and in the antennae of insecis, although it 

 is not to be supposed that they all serve for the sense 

 of smell. Newport * alludes to the " pits " ; but they 

 were first described by Erichsont; while Burmeister if 

 suggested that there are two classes — those containinr-- 

 a hair, and those in which there is none. The pits are 

 only found in certain regions, and have certainly some 

 specific function. In the stag-beetle (Lucanus cervus) 

 the terminal plate of the antenna shows two large pits, 

 one on each side, and nearly opposite one another. In 

 other Lamellicorn beetles, as, for instance, in the cock- 

 chafer (Melolontha vulgaris), they are very numerous. 

 Lespes§ supposed them to be closed sacs, each containing 

 an otolithe. They certainly do present this appearance, 

 but the existence of any otolithe has been conclusively 

 disproved by Claparede,|| Glaus, Hicks, and others. 



Graber thought 1[ that he had discovered an organ 

 of hearing containing an otolithe in the antennas of 

 certain Diptera. Mayer,** however, has since examined 



* Tranmctions of the Entomological Societij of London, vol. ii. 



t " De Fabrica et usu anteimariini in lusectis." 1847. 



X "Beol). fiber den feincren Bau der Fiililirfachur der LaincUi- 

 coniier." 1848. 



§ •' JIi'iu. sur I'appareil auditif des Inseotes,'' Ann. Sci. Nat , IS.JS. 



II '■ Sur Its piijtendua organes auditifs des Autenues chez k-a 

 Cole'opteres," Ann. Sri. Nat., 18.38. 



t " L'eber neue otocystenartige Siniietorgaue der Insekten," Arch, 

 fur Mio. Anat, 1S79. 



** "Sopra certi orgaui di Senso nelle Antonue dei Diiteri," Ileale 

 Aco. dei Lincei, 1S78-7IJ. 



