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. '^^* With these last, the anastomosing canals, which connect the 

 primary trunks, are often double. ""> With the Palpicornes, and Lamelli- 

 cornes, 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. 



I. 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 Cams, Entdeck. &c. Taf. III. (larva aud pupa 

 of an Ephemera). 



13 Suckow, in Heusin^erKi Zeitsch. II. Taf. I. 

 II. (larva and imago of an Aesclina). 



IC With the Locustidae, Achetidae and Mantidae ; 

 see L. Dufour, Recherch. sur les Orthopt. &c. p. 

 269, PI. I. fit;. 1 lOedipoda), and Marcel de Serres, 

 Mem. du Mus. IV. p. 331, PI. IV. (16) (Mantis), 

 also in Isis, 1819, p. 627, Taf. IX. 



ir Marcel de Serres, loc. cit. PI. III. (15) 

 (Truxalis), and L. Dufour, loc. cit. PI. I. (Oedi- 

 poda). 



15 See Burmeister, Trans. Entom. Soc. I. PI. 

 XXIV. fig. 9 (larva of Calosoma sycophanta), 

 and Audouin, Ann. d. Sc. Nat. IX. 1826, PI. 

 XLIII. fig. 3 (Lytta vesicatoria). 



VJ See L. Dufour, Ann. d. Sc. Nat. VIII. 1826, 

 p. 23, PI. XXI. bis. fig. 1, and Pictet, M^m. de 

 Genive, VII. p. 397, fig. 6 (Hammaticherus 

 heros). 



■M Swammerdamm, Bib. der Nat. Taf. XXIX. 

 fig. 9 (Geotrupes nasicornis), and Straus, Con- 

 sid. &c. PI. VII. {Melolontha vulgaris). See, 

 also, for the Coleoi)tera in general, L. Dufour, 

 Ann. d. Sc. Nat. VIII. 1S26, 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 L. Dufour, Recherch. 

 sur les Ilemipt. 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. 



S For a long 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. XJntersuch. iiber die Haushalt. der Insekt. 

 1817, p. 27). This chemical proof was furnished 

 by Brugnatelli and Wurzer (Meckel's Deutsch. 

 Arch. II. 1816, p. 629, and IV. 1818, p. 213), with 

 Bombyx rnori. Subsequently, the existence of this 

 acid has been confirmed by Clievreul with Melo- 

 lontha vulgaris (Straus, Consid. &c. p. 251), 

 and by Audouin with Lucanus cervus and PoHs- 

 tes gallica (Ann. d. Sc. Nat. V. 1836, p. 129). 

 See, also, Meckel, Ueb. die Gallen — und Ilarnor. 

 gane der Insekten, in his Arch. 1826, p. 21, and 

 Groshans, De System, uropofit., quod est Radiat. 

 Articulat. et Mollusc. Acephalorum. 1837, p. 39. 



