440 THE INSECTA. $ 345. 
The true Neuroptera, in all their states, have a pretty simple trachean 
system provided with two lateral trunks, But with the Orthoptera, on the 
contrary, this system is usually very complicated. It is, indeed, less so 
with the Blattidae, Forficulidae, Ephemeridae; and Perlidae ;“ but with 
the Libellulidae, the two lateral trunks are very large and arise from the 
trachean branchiae together with two other trunks.” With the other 
Orthoptera, the tracheae are very numerous and disposed according to the 
second type or form, their trunks being connected by a multitude of volu- 
minous, longitudinal, and transverse anastomoses, giving the whole a reti- 
culated aspect." With the Acrididae, most of the transverse anastomoses 
have large air-reservoirs on their course,” 
With the Coleoptera, the tracheae are always highly developed, and 
disposed, with the larvae, after the first type, but with the imagines, after 
the second. 
primary trunks, are often double, 
With these last, the anastomosing canals, which connect the 
With the Palpicornes, and Lamelli- 
scornes, this system is most highly developed,—the fine as well as the 
larger tracheae having a multitude of terminal vesicles. 
CHAPTER VIII. 
ORGANS OF SECRETION. 
L. Urinary Organs. 
§ 345. 
The Malpighian vessels, which are widely spread among the Insecta in 
all their conditions,” must now, since uric acid has been detected in their 
secretion, be regarded as Kidneys. 
14 See Swammerdamm, Bib. der Nat. Taf. XIV. 
and Carus, Entdeck. &c. Taf. III. (larva and pupa 
of an Ephemera). 
15 Suckow, in Heusinger’s Zeitsch. II. Taf. I. 
II. (larva and imago of an Aeschna). 
16 With the Locustidae, Achetidae and Mantidae 5 
see L. Dufour, Recherch. sur les Orthopt. &c. p. 
269, Pl. I. fig. 1 (Oedipoda), and Marcel de Serres, 
Mém. du Mus. LY. p. 331, Pl. IV. (16) (Mantis), 
also in Isis, 1819, p. 627, Taf. IX. 
W7 Marcel de Serres, loc. cit. Pl. III. (15) 
(T'rucxatis), and L. Dufour, loc. cit. Pl. I. (Oedi- 
oda). 
i 18 See Burmeister, Trans. Entom. Soc. I. Pl. 
XXIV. fig. 9 (larva of Calosoma sycophanta), 
and Audouin, Ann. d. Sc. Nat. IX. 1826, Pl. 
XLIII. fig. 3 (Lytta vesicatoria). 
19 See L. Dufour, Ann. d. Sc. Nat. VIII. 1826, 
p. 23, Pl. XXI. bis. fig. 1, and Pictet, Mém. de 
Genéve, VII. p. 397, fig. 6 (Hammaticherus 
heros). 
20 Swammerdamm, Bib. der Nat. Taf. XXIX. 
fig. 9 (Geotrupes nasicornis), and Straus, Con- 
sid. &c. Pl. VII. (Melolontha vulgaris). See, 
also, for the Coleoptera in general, L. Dufour, 
Ann. d. Sc. Nat. VIII. 1826, p. 22. 
1 As yet only Coccus, Chermes, and the Aphi- 
didae, have been found wanting the Malpighian ves- 
sels; see Ramdohr, Verdauungswerk. d. Insekt. 
p. 198, Taf. XXVI. and LZ. Dufour, Recherch. 
sur les Hemipt. p. 116, fig. 114. I have been 
unable to find them with the Strepsiptera in their 
various stages of development. The male imagines 
of Xenos Rossii, alone, have presented to me, at 
the extremity of the digestive canal, a singular 
glandular appendage resembling a cribriform lobe, 
and which serves, perhaps, as a urinary organ. 
2 For a Jong time the Malpighian vessels were 
regarded as biliary organs, when Rengger ex- 
pressed the opinion that they were urinary organs, 
without, however, having demonstrated the pres- 
ence of uric acid in their secreted product (Phys- 
iol. Untersuch. iiber die Iaushalt. der Insekt. 
1817, p. 27). This chemical proof was furnished 
- by Brugnatelli and Wurzer (Meekel’s Deutsch. 
Arch. II. 1816, p. 629, and IV. 1818, p. 218), with 
Bombyx mori. Subsequently, the existence of this 
acid has been confirmed by Chevreul with Melo- 
lontha vulgaris (Straus, Consid. &c. p. 251), 
and by Audouin with Lucanus cervus and Polis- 
tes gallica (Ann. d. Se. Nat. V. 1836, p. 129). 
See, also, Mechel, Ueb. die Gallen — und Harnor. 
gane der Insekten, in his Arch. 1826, p. 21, and 
Groshans, De System. uropoét., quod est Radiat. 
Articulat. et Mollusc, Acephalorum. 1837, p. 39. 
