262 THE entomologist's record. 



external chitinous skeleton of an insect makes it possible that the 

 hairs are even more effective than usual as intermediaries in the trans- 

 mission of the external force to the nerve termination. It is also 

 probable that the different types of hairs receive different sorts of im- 

 pressions, which ultimately produce the idea of touch, pressure, weight, 

 etc. (2) Smell. — The sense of smell is very acute in Lepidoptera, 

 and a large number of species of both moths and butterflies are known 

 to possess special organs for the emission of odours. The rapidity with 

 which NocTuiDEs, Tortricides, etc., find sugar, spread as a bait on 

 trees ; the ease with which all Lepidoptera detect the right food-plant on 

 which to deposit their eggs, and the wonderful cases of assembling, 

 which have been chronicled, are all sufficient to show that some 

 marvellous power of perception is owned by Lepidoptera, and all 

 logical enquiry suggests that this power must closely resemble our 

 sense of smell. We have elsewhere"-'' enlarged considerably on this 

 topic, and need only add here that there are many reasons why the 

 pits and rods of the antennaj should be regarded as the peripheral 

 organs of this sense. Viallanesf says the antennal nerve is provided 

 with two roots ; one, ventral, composed exclusively of fibres affected by 

 special sensibility, arises from the olfactory lobe ; the other, dorsal, which 

 includes at once motor fibres and fibres of general sensibility, arises 

 from the dorsal lobe of the deutocerebron. It has been stated that 

 " Lepidoptera possess this faculty (gift of scent) beyond doubt, and as 

 the air inhaled is the carrying medium, we must look to the spiracles 

 as the organs of smell." This opinion is absurd, for it rests upon the 

 assumption that the condition found in the higher vertebrates must 

 also obtain in lower forms. Air is doubtless the carrying medium, 

 but air has access to the rods in the pits of the antennae. That 

 simple diffiision of the air containing the olfactory particles is sufficient, 

 and that a current of air is not needed to excite the nerves, is 

 abundantly proved by the conditions existing among the lower verte- 

 brates (sharks, Aviia calva, Petromyzon marimis, etc., have been 

 instanced). HauserJ states that bees and wasps have 14,000 to 

 15,000 cavities, and about 200 cones in each antenna ; the leaf-wasps 

 a smaller number. The flesh and dirt flies have 60 to 150, while the 

 flies that live on plants have only 5 to 6 on each feeler. Hence the 

 number of cavities (pits and rods) and cones occurring in an antenna 

 appears to be correlated with the importance of the power of dis- 

 tinguishing scent, in the life of the species. 8. Hearing. — It is extremely 

 probable that, from Child's 1| experiments on the Cw^ic u/rtf and C7r/ro??o- 

 midae, that the antennae function as organs of hearing. Bodine 

 thinks that the set of apparatus described under section 6 {ante, p. 227), 

 is especially adapted to the perception of any sort of delicate pulsation of 

 sound waves. 4. Taste. — It has been supposed by some biologists 

 that the rods and cones of the antennae function as organs of 



* Random Recollections of WoodUmd, Fen and Hill, 2nd Edn., pp. 22-24 ; 

 124-127. * British Noctuae and their Varieties, vol. iii., pp. iv-viii. * British 

 Biitterjiies, pp. 19-20 ; 02-03. 



+ " Etudes histologique et organologique sur les centres nerveux et les Organes 

 des sens des Animaux articules." — Ann. de Sci. Nat. Zoologie, 8 Series, T. 14, 

 Paris, 1893, pp. 409—456. 



t Popular Science Monthly, vol. xxiii., p. 284. 



II Zeit.f. u\ Zool., Bd. 38, 1894. pp. 475—528. 



