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 Ganglion frontale,a second ganglion. It runs along 
the cesophagus, 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 transversiz 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 cannot, 
therefore, be regarded as properly of a voluntary nature. 
CHAPTER IV. 
ORGANS OF SENSE. 
§ 882. 
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. 
fig. 1-5, and J. Muller, Nov. Act. Nat. Cur. loc. 
cit, p. 85, Tab. VIII. fig. 1,3. These two anato- 
mists have given, moreover, details with figures on 
the splanchnic nerves of Libeliula, Blatta, Man- 
tis: and Gryllus. 
i Swuammerdamm (Bib. der Nat. p. 132, Taf. 
XXVIII. fig. 2) has observed the Nervus recur- 
rens in the larva of Oryctes nasicornis. Miller 
(Nov. Act. Nat. Cur. loc. cit. p. 94, Tab. VII. fig. 
4, 5) has figured it with Lucanus and Dytiscus. 
Straus (Consid. &c, p. 406, 391, Pl. IX.) has ob- 
served with Melolontha, not only the single 
nerve,.but also the double system which, however, 
he mistook for the accessory ganglia of the brain ; 
Brandt (Mediz. Zool. II. p. 103, 118, Taf. XVII. 
fig. 8, 4, Taf. XIX. fig. 20) was the first to under- 
stand the true nature of this system with Meloé and 
Lytta. See, moreover, Burmeister (Handb. &c. 
Taf. XVI. fig. 8 (a larva of Calosoma)), Newport 
(Philos. ‘iraas. 1834, Pl. XIII. fig. 4,5 (imagoand 
larva of Timarcha tenebriosa), and Cyvlopaed. 
&c. fig. 405, 412, 416-418 (Timarcha, Meloe and 
Lucanus)) 3 also Schisdte, in Kréyer’s Naturh. 
Tidskrift. LV. p. 104, Pl. I. Acilius. 
8 Although Lyonet (Traité, &c., p. 98, 201, Pl. 
IV. fig. 5, Pl. IX. fig. 1) had already described this 
respiratory system with the larva of the goat-- 
moth, under the name of brides dpinieres, it is 
Newport who has recently called the attention of 
anatomists to this subject, by furnishing, with ad- 
mirable details, the disposition of. this respiratory 
plexus, in the larva, pupa and imago of Sphing 
ligustri (Philos. Trans. 1832, Pl. XII. fig. 4, 
1834, Pl. XIII. &c., and 1836, Pl. XXXVI., Faso 
Cyclopaed. loc. cit. p. 947, fig. 400). See, *also, 
Miiller’s ideas (Archiv, 1835, p. 82) on the nature 
of this nervous system. With various Coleoptera 
and Orthoptera, with Locusta, Gryllotalpa, and 
Carabus, the single roots arise, according to New- 
port, from small ganglia, at the points where are 
given off the Wervi transversi. 
1 For the senses of the Insecta in general, be- 
side the works of Spence and Kirby, Burmeister 
aud Lacorduire, see Schelver’s Versuch einer 
Naturgesch. d. Sinneswerkz. bei d. Insekten u. 
Warmern, 1798, a work in which are related the 
opinions of the older naturalists on this subject. 
2 The tactile sense of the palpi is of great service 
to Insecta when they eat; for these organs are used 
not only to feel the food but also to retain, and con 
vey it between the jaws. 
