414 THE INSECTA. <§, 332. 



The Coleoptera have, in both their larval and their perfect states, a 

 feebly-developed double nervous system arising from two pairs of ganglia, 

 and a highly-developed Nervus recurrens which, with a few species, forms, 

 directly behind the Gaiiglion frontale, a second ganglion. It runs along 

 the oesophagus, and usually forms, posteriorly, still another ganglion, and 

 then divides dichotomously.*^' 



A great number of the Insecta have, in all their states, another system 

 of nerves, called Respiratory nerves, which, in view of their functions, 

 ought very properly to be classed among the mixed nerves, for they con- 

 tain not only motor, but also vegetative fibres. This system arises by 

 several single roots from the longitudinal commissures of the ventral cord. 

 Each of these roots divides into two Nervi transversa which deviate from 

 each other at right angles, and anastomose with the ganglia of the ventral 

 chain and with its peripheric nerves, receiving at the same time organic 

 fibres from the ganglia of the double splanchnic system. These respiratory 

 nerves are distributed to the large trachean trunks, and especially to the 

 muscles of the stigmata. The respiratory movements of Insecta caanot, 

 therefore, be regarded as properly of a voluntary nature. <*> 



CHAPTER IV. 



ORGANS OF SENSE. 



§ 332. 



The sense of Touch appears to be seated, with Insecta, in very different 

 parts of the body.'^' It is chiefly located in the palpi of the mouth, 

 which, for this purpose, are usually terminated by a soft surface.*^* The 

 antennae, also, serve as tactile organs, but in a very variable manner, ac- 

 cording to their forms, the degree of their development, and the habits of 



plete ; see Brandt, Bemerk. &c. p. 27, Taf. III. IV. fig. 5, PI. IX. fig. 1) had already described this 

 fig. 1-5, and J. Muller, Nov. Act. Nat. Cur. loc. respiratory system with the larva of the goat- 

 cit. p. 85, Tab. VIII. fig. 1, 3. These two anato- moth, under the name of brides ipinieres, it is 

 mists have given, moreover, details with figures on Newport who has recently called the attention of 

 the splanchnic nerves of Libellula, Blatta, Man- anatomists to this subject, by furnishing, with ad- 

 tis and Gryllus. mii'able details, the disposition of this respiratory 

 ■7 Swammerdamm (Bib. der Nat. p. 132, Taf. plexus, in the larva, pupa and imago of Sphinx 

 XXVIII. fig. 2) has observed the Ifervus recur- ligustri (Philos. Trans. 1832, PI. XII. tig. 4, 

 rens in the larva of Oryctcs nasicurnis. MuUer 1834, PI. XIII. &c., and 1836, PI. XXXVI., also 

 (Nov. Act. Nat. Cur. loc. cit. p. 94, Tab. VII. fig. Cyclopaed. loc. cit. p. 947, fig. 400). See, also, 

 4, 5) has figured it with Lucanus and Dytiscus. Mu//er''s ideas (Archiv, 1835, p. 82) on the nature 

 Straus (Consid. &c. p. 406, 391, PI. IX.) has ob- of this nervous system. With various Coleoptera 

 served with Melolontha, not only the single and Orthoptera, with Locusta, Gryl/ota/pa, and 

 nerve, but also the double system which, however, Carabus, the single roots arise, according to New- 

 he mistook for the accessory ganglia of the brain ; port, from small ganglia, at the points where are 

 Brandt (Mediz. Zool. II. p. 103, 118, Taf. XVII. given off the Nervi transversi. 

 fig. 3, 4, Taf. XIX. fig. 20) was the first to under- 1 For the senses of the Insecta in general, be- 

 stand the true natui'e of this system with Meloe and side the works of Spence and Kirby, Burmeister 

 Lytta. See, moreover, Burmeister (Ilandb. &c. and Lacordaire, see Sc/ielver''s Versuch einer 

 Taf. XVI. fig. 8 (a larva of Calosoma)), Newport Naturgesch. d. Sinneswerkz. bei d. Insekten u. 

 (Philos. Trans. 1834, PI. XIII. fig. 4, 6 (imago and Wurmern, 1793, a work in which are related the 

 larva of Timarcha tenebriosa), and Cyclopaed. opinions of the older naturalists on this subject. 

 &c. fig. 405, 412, 416-418 {Timarcha, Meloe and ^ The tactile sense of the palpi is of great service 

 Lucanus)) ; also Schiiidte, in Kroyer's Naturh. to Insecta when they eat; for these organs are used 

 Tidskrift. IV. p. 104, PI. I. Acilius. not only to feel the food but also to retain, and cou- 

 3 Although /..(/on ei (Trait6,&c., p. 98, 201, PI. vey it between the jaws. 



