412 THE INSECTA. § 331. 
not yet been definitely fixed. The first type consists of an absence of 
all the longitudinal commissures, as is the case with most of the Lamelli- 
cornes, the Curculionidae, and the Scolytidae. Here, the ventral cord is 
limited to three ganglia connected together ; of these, the first corresponds 
to the prothoracic, and the second, the larger, to the second and third 
thoracic ganglia. This last is succeeded by an oblong, ganglionic mass, 
representing the concentrated abdominal portion of the cord, arfd from 
which arise the nerves of the muscles of the abdomen.” In the second 
type, the abdominal portion of the cord occupies the entire length of the 
body. This is the case with the Cistelidae, Oedemeridae and Cerambyci- 
dae, which have five ganglia in the abdomen.” With the larvae of the 
‘Coleoptera, these two types are more clearly defined, there being no inter- 
mediate forms.” 
§ 331. 
The Splanchnic nervous system consists, with the Insecta, in all their 
states, of a single and a double nervous cord. Sometimes the first, some- 
times the second of’ these is the more developed. 
The single Stomato-gastric nerve arises from the anterior border of the 
cerebral hemispheres, by two short filaments, which, directly in front 
of the brain, meet in a ganglion (Ganglion frontale) lying upon the cesoph- 
agus. 
go to the upper lip; while, from the 
18 There has recently appeared a very detailed 
memoir, accompanied with beautiful figures, on the 
nervous system of the Coleoptera, by Blanchard ; 
see Ann. d. Sc. Nat. V. 1846, p. 273, Pl. VIIL.—XV., 
and Régne animal. illustr. Insectes, Pl. III. III. 
bis. and IV. (Melolontha, Carabus, Otiorhyn- 
chus, Cerambyz). 
19 See Straus, Considér. &c. p. 391, Pl. IX. fig. 
1 (Melolontha vulgaris), and Blanchard, loc. cit. 
An analogous concentration of the nervous system 
occurs in the families of Histeridae, Gyrinidae, 
Nitidulidae, and Scaphididae,where the ventral por- 
tion forms a single oblong ganglion, while the three 
thoracic ganglia are connected by double longitudi- 
nil commissures. In most of the other families, the 
three thoracic ganglia are more or less separated, 
and the abdominal portion is modified in various 
ways. With the Endomychidae, Meloidae and 
Chrysomelidae, there are only four abdominal 
ganglia connected by very short double commis- 
sures ; see Audouin, Ann. d. Sc. Nat. IX. 1826, 
p. 36, Pl. XLII. fig. 16 (Lytta); Brandt, Mediz, 
Yool. IL. p. 103, Taf. XVII. fig. 2, Taf. XIX. fig. 
19 (Melog and Lytta) ; Newport, Cyclopaed. loc. 
cit. IL. p. 950, fig. 408 (Timarcha) and Joly, 
Ann. d. Sc. Nat. IL. 1844, p. 24, Pl. IV. fig. 16 
(Colaspis). With the Dytiscidae, and with Bytu- 
rus, there are six abdominal ganglia, and the com- 
missures are also very short; see Burmeister, 
Handb. loc. cit. Taf. XVI. fig. 9 \Dytiscus). This 
figure, however, is not fully exact, if compared 
with that of Blanchard (loc. cit. p. 343, Pl. X. fig. 
1). With the Staphylinidae, Silphidae, and Hy- 
drophilidae, the abdominal portion, although com- 
posed of eight ganglia, is not. prolonged much 
into the abdomen ; it is longer and composed of 
six to seven ganglia with the Carabidae, Lu- 
canidae; and Pyrochroidae ; see ZL. Dufour, 
Ann. d. Sc. Nat. VIIE. 1826, p. 27, Pl. XXTI. bis, 
“fig. 2 (Carabus), and Ibid. XIII. 1840, p. 332, 
Pl. VI. fig. 9 (Pyrochroa). It is even still longer 
From this ganglion are given off several nervous filaments which 
opposite side, arises a simple nerve 
and composed of eight ganglia with the Elateridae, 
Cleridae and Telephoridae. 
20 See Blanchard, loc. cit. 
21° With those species of the Lamellicornes, and 
Curculionidae, whose ventral cord is very much 
concentrated, the eleven large component ganglia 
are, with the larvae, united into one knotty mass, 
without any trace of issures ; see § = 
damm, loc. cit. p. 131, Taf. XXVIII. fig. 1 (Oryc- 
tes) ; L. Dufour, Ann. d. Sc. Nat. XVIII. 1842, 
p.1%0, Pl. IV. fig. 11 (Cetonia); Burmeister, 
Zur Naturgesch. d. Calandra, p. 13, fig. 13, 14; 
Blanchard, Ann. a. Sc. Nat. loc. cit. Pl. XY. fig. 
1 (Calandra). With the larvae of the Meloidae, 
Pyrochroidae, Lucanidae, Chrysomelidae, Tene- 
brionidae, as well as of most of the other families 
of the Coleoptera, the ventral chain occupies nearly 
the entire length of the body, and is composed of 
eleven ganglia having double commissures ; the 
thoracic ganglia exceed but little in size those of 
the abdomen ; see Brandt, Mediz. Zool. II. p, 105, 
Taf. XVII. fig. 20, Taf. XIX. fig. 31 (Meloé and 
Lytta); L. Dufour, Ann. d. Sc. Nat. XIII. 1840, 
p. 327, Pl. V. fig. 8 (Pyrochroa), and XVIII. 
1842, p. 172, Pl. V. fig. 17 (Dorcyus) ; Newport, 
Cyclopaed. loc. cit. p. 943, fig. 404 (Timarcha) ; 
Joly, Aon, d, Sc. Nat. If. 1844, p. 24, Pl. IV. fig. 
14 \Colaspis), and Blanchard, Ibid. Pl. XV. fig. 
7, Pl. X. fig. 5 (Chrysomeda and Tenebrio). It 
is only with the larvae of the Carabidae, Silphidae, 
Staphylinidae and Diaperidae, that the ventral 
cord, although composed of eight ganglia, does not 
extend into the last abdominal segments; while 
that of the larvae of the Dytiscidae, composed of 
seven ganglia, does not reach beyond the middle 
of the abdomen ; see Burmeister, Trans. of the 
Entomol. Soc. Lond. I. p. 239, Pl. XXIV. fig. 9 
(Calosoma) ; Blanchard, Ann. d. Sc. Nat. loc. cit. 
Pl. IX. fig. 3, 5, Pl. XI. fig. 4, PL X. fig. 2 (Sil- 
pha, Staphylinus, Diaperis, and Dytiscus). 
s 
