62 OLFACTORY PITS. 



the antennae and mandibular palpi of the crayfish 

 (Astacus fluviatilis) but I do not find any further 

 description of them. On the other hand, in insects they 

 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 insects, 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 Erichson f ; while Burmeister { 

 suggested that there are two classes — those containing 

 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 eervus) 

 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 antennae of 

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



* Transactions of the Entomological Society of London, vol. ii. 



t " De Fabrica et usu antennarum in Insectis." 1847. 



X "Beob. iiber den feineren Bau der Fiililerfachur der Lainelli- 

 cornier." 1848. 



§ "Mem. sur I'appareil auditif des Insectes," A^m. Sci. Nat , 1858. 



11 "Sur les pretendus organes auditifs des Anteunes chez les 

 Coleopteres," Ann. Sci. Nat., 1858. 



^ " Ueber neue otocystenartige Sinuesorgane der Insekten," Arch, 

 fur Mic. Anat., 1879. 



** " Sopra certi organi di Senso nelle Autenne dei Ditteri," Jleale 

 Ace. dei Lincei, 1878-79. 



