§ 331. THE INSECTA, 413 
(Nervus recurrens) which passes over the cesophagus to the stomach, giv- 
ing off branches right and left. Reaching the stomach, it divides, after 
having formed a ganglionic enlargement, into two principal branches. 
The double Stomato-gastric nerve consists of one, two, or three pairs of 
small ganglia, situated behind the brain, on each side of the cesophagus, 
and communicating with each other, with the posterior extremity of the 
brain, and with. the Nervus recurrens, by delicate filaments. ‘hese fila- 
ments send fine threads to the cesophagus, and, at certain points, anastomose 
with the single nerves.” 
With the Hemiptera, a single Splanchnic nerve has been observed, and, 
for the double system, there has been seen, on each side of the esopbagus, 
two small ganglia, one behind the other. 
With the Diptera, the splanchnic system appears to be present; at least, 
there has been observed on the Chyliferous stomach of the Hippobescidae, 
a pair of filaments belonging, probably, to the double system. 
The Lepidoptera have a highly-developed Nervus recurrens, which often 
forms, with the caterpillars, several small ganglia lying bthind each other 
on each side.of the brain, and connected together by a double nervous 
arch. The double system arises on each side of the cesophagus, from two 
ganglia, situated one behind the other, which, with the caterpillars and 
pupae, are often approximated to a blending together, and which send off, 
beside the filaments anastomosing with the recurrent nerve, threads to the 
dorsal vessel.“ The Hymenoptcra,® Neuroptera, and Orthoptera, also, 
have the two kinds of splanchnic systems. The double trunks are highly: 
developed with the Acrididae, and the Gryllotalpida, and have two pairs 
of ganglia at their upper extremity, beside one or two on their course; 
while, with the Libellulidae, Blattidae, and especially the Phasmidae, the 
single nerve is the most developed.“ 
1 For the Splanchnic nervous system of the In- 
Becta, of which Swammerdamm had already ob- 
served the recurrent nerve, see, beside the gene- 
ral works of Burmeister (Handb. &c. I. p. 308), 
and Lacordaire (Introduct. &c. II. p. 214), espe- 
cially J. Miller, Nov. Act. Acad. Nat. Cur. XIV. 
1828, p. 73; Brandt (Isis, 1831, p. 1103, also his 
Bemerk. iiber die Mundmagen-oder Hingeweidener- 
ven d. Evertebr. 1835, p. 16, or Ann. d. Sc. Nat. 
V. 1836, p. a and Newport, Cyclop. &c. loc. 
eit. IL. p. 957). 
2 Meckel (Beitr. zur vergleich. Anat. I. p. 4) 
has observed the Nervus recurrens in the com- 
mon Cicada, and Brandt (Bemerk. &c. p. 23, Taf. 
II. fig. 1, 2) has observed the same with Lygaeus, 
and at the same time the ganglia of the double 
system. 
3See L. Dufour, Ann.d. Sc. Nat. III. 1845, p. 67. 
4 The recurrent nerve was first discovered in the 
silk-worm by Swammerdamm (Bib. der Nat. p. 
132, Taf. XXVIII. fig. 3, g.). Subsequently, Ly- 
onet (Traité, &c., p. 577, Pl. XIL. fig. 1, Pl. XIII. 
fig. 1, Pl. XVI. fig. 14, Pl. XVIII. fig. 1) de- 
scribed with the larva of the Goat-moth, the 
double system and its relations with the dorsal 
vessel. Since then, the two systems have been ob- 
served in the larvae, pupae, and imagines of various 
Lepidoptera; see Suckou (Anatom. physiol. Unter- 
such. 40, Taf. VIT. fig. 33-38, (pupa and imago of 
Gastropacha pini)), who has described the double 
system and the cardiac nerve. See, also, J. Mul- 
ler (Nov. Act. Nat. Cur. loc. cit. p. 97 (the recur- 
rent nerve of a larva of Sphina)), and Brandt 
isis, loc. cit. p. 1104, Taf. VII. fig. 3, 4, and Be- 
merk. &c. p. 20), who has described the two sys- 
30* 
tems with the imago and larva of Bombyx mori. 
The works of Newport (Philos. Trans. 1832, p. 
383, Pl. XII. XIII., and 1834, p. 389, Pl. XH. 
XIV. ) on the larva and imago of Sphing lPeustri, 
are very distinguished. 
5 See Treviranus (Verm. Schrift. IIT. p. 59), 
who thinks he has observed the Wervus recur- 
rens with Apis mellifica ; Brandt, also (Medizin. 
Zool. Il. p. 203, Taf. XXV. fig. 32, and his Be-~ 
merk, &c. p. 22), has described the two systems in 
this species, and in the Bumble-bee (Apis terres- 
tris). 
6 According to Burmeister (Handb. &c. I. p. 
310, Taf. XVI. fig. 6 (Gryllus migratorius)), the 
recurrent nerve leaving the frontal ganglion, runs 
backwards and -ends, after a short course, in a 
ganglion which connects by two filaments with the 
internal ganglia of the double system. These 
last send off several branches to the vesophagus, 
and connect, through two filaments, with the exter- 
nal ganglia of thesame system. From these exter- 
nal ganglia arise two lateral trunks which run 
along the cesophagus and are distributed to the 
gizzard, forming a nervous plexus having four 
ganglia. See, also, for the same species, Brandt, 
in the Isis, 1831, p. 1104, Taf. VII. fig. 5. Accord- 
ing to this last author (Bemerk. &c. p. 29, Taf. IT. 
fig. 7-9), the double system of Gryllotaipa is sim- 
ilarly disposed, only the nervous plexus of the giz- 
zard arises from two posterior ganglia of the twe 
trunks. See, also, for that of Gryllotalpa, L. 
Dufour, Recherch. sur les Orthopt. &c.-p. 235, 
Pi. III. fig. 22. With Phasma ferula, the four 
anterior ganglia of the single system are small, but, 
for compensation, the double system is very com- 
