442 THE INSECTA. <^ 346. 



of the Geocorisae.'^ AVith some species, their excretory ducts form one or 

 two vesicular dilatations situated above the colon.'*' It is only with a few 

 Geocorisae, and with the Cicadidae, that the extremities of these canals are 

 free.''" With this last group, and with the Cercoj)idac, they creep with a 

 portion of the intestine, between the tunics of the ante-stomach, before 

 opening into the lower extremity of the true stomach."" 



With the Diptera, there are four long urinif'crous vessels. The Cullci- 

 dae and Psychodae, alone, by exception, have five.'^* With very many 

 species, these canals are united in twos, and open, by a common excretory 

 duct, into the lower extremity of the stomach.''*' Loop-like anastomoses 

 occur only with the Tipulidae, Leptidae, and Bombylidae.*"' 



With the Lepidoptera, there are nearly always six long, free, uriniferous 

 tubes, M'hich open into the stomach by two excretory ducts. *^'" 



The Hymenoptera are distinguished for their considerable number of 

 these vessels, which are usually short and surround the pylorus in numbers 

 of twenty to one hundred and fifty."" With the Orthoptera, these vessels 

 are inserted in a similar manner, '^-' but are often much more numerous.''* 

 The Termitidae, alone, form an exception, — having only six.'^^' 



The true Neuroptera are distinguished from the Orthoptera in that their 

 vessels of this nature are long, flexuous, and only six to eight in number."^' 



With the Coleoptera, they are usually long, make numerous convolutions, 

 and never exceed four or six in number. '''*' When four, they are nearly 

 always joined by twos at their extremity ; and when six, they are often 

 attached by their extremities to the colon.''''' 



The urinary vessels of the larvae and pupae resemble somewhat those of the 

 perfect Insecta.""' With the larvae of certain Hymenoptera, and Orthoptera, 



3 With the Naucoridae, Nepidae, with Salda, 12 With the Ephetneridae, alone, the form of 



CapsHS and Redm^iux. With Dortkesia, tlie these canals is somewhat different, in that their free 



fom- canals form also two short loops ; see L. Du- extremities are nearly always thickened, and that 



four, Recherch. &c. p. 19, PI. I.-IX. the excretory ducts take one or two spiral turns. 



* Pentatoma, Teti/ra, Pyrrkocoris, Lygaeus, 1"' See L. Diifoiir, Recherch. siir les Orthopt. 



Gerris, Stenocep/ialus. &c. PI. I.-IV. XI. XIII. Oryllotalpa is distin- 



5 Cimex, Ploiaria, Miris, A/ydus a.ncl Coreus. guished from the other Orthoptera in that the 

 In the last two genera the uriniferous canals, free, urinary canals are disposed fasciculate and termi- 

 terminate at the iiylorus in a common reservoir, nate in a single excretory duct. 



With Alyd'in, Aradiis, Aneurus; Cixius, Is.ius, H L. Dufour, Recherch. loc. cit. PI. XIII. fig. 



and Asiraca, they unite in twos in a common ex- 196. 



crctory duct. With Psylla, they consist only of 15 L,. Dufour, Ibid. PI. XI.-XIII. There are 



four rudimentary caeca; see L. Dufour, Recherch. six of these vessels with the I'hryganidae, Sialidae, 



loc. cit. Panorpidae, Rhapididae : and eight with the Myr- 



6 It was a long time before there was an exact meleonidae and Ilemerobidae. 



idea of the canals with Cicada. Doyire (Ann. ifi There are f lur urinary vessels with the Cara- 

 d. Sc. Nat. XI. 1839, p. 81, PI. I.) was the first bidae, Staphylinidae, Gyrinidae, Palpicornes, La- 

 who perceived that they penetrated between the mellicornes, Cantharidae, and ISuprestidae ; six 

 tunics of the stomach ; but he supposed they re- with the Byrrhidae, Nitidulidae, Dermestidae, 

 appeared on its surface after a short course. He Cleridae, Meloidae, Pyrochroidae, Bruchidae, Bos- 

 did not, therefore, attribute to these insects, only tricidae, Capricornes, Chrysomelidae, and Coccin- 

 two uriniferous vessels. This last error has been ellidae. 

 rectified by L. Dufour (Ibid. XII. p. 287). 1" For the uriniferous canals of the Coleoptera, 



^ See L. Dufour, Ann. d. Sc. Nat. XIX. loc. see, beside Ramdohr, and Sacknw, loc. cit., L. 



cit. PI. VIII. fig. W (^Anopheles). Dufour, Ann. d. Sc. Nat. 1824, II.-IV. ; 18.34, I. 



« With the Muscidae, Oestridae, Conopidae, J>1. II. III.; ISIO, XIII. PI. V. VI.; XIV. PI. XI.; 



Syrphidae, and Hippoboscidae. With the Stratio- XI.X. PI. VI. With Donacia, the six vessels 



mydae, the four canals unite into one excretory have a very peculiar aspect. Two pairs unite 



duct; see Swammerdamm, Bib. der Nat. Taf. loop-like at their posterior extremities, and their 



XLI. fig. 6 {Siratiomyx) j L. Dufour, loc. cit. PI. anterior ends unite in a common reservoir ; while 



VIII. fig. 28 (Sargus). the third pair are free and open isolately at the 



9 Ramdohr, loc. cit. Taf. XX. pylorus ; see L. Dufour, Ann. d. Sc. Nat. 1824, 



10 With Pterophorus and Yponomenta, Suckow IV. PI. VII. fig. 7, 8, and 1844, XIX. PI. VII. fig. 

 has found only four uriniferous vessels (loc. cit. Taf. 10. 



IX. fig. 15J, 161). IH Beside Ramdohr, and Suckoiv, loc cit., see L. 



11 See L. Dufour, Recherch. sur les Orthopt. Dufour, Ann. d. Sc. Nat. .XII. 1839, PI. I.; XIII. 

 PI. III.-X. The smallest number of these canals PI. V.; and XVIII. PI. IV. (larva of a Ti]iulide, a 

 is found with the Formicidae, Cynipidae, and Ich- Sapromyza, a Pyrochroa, and of a Cetonia, &c.) ; 

 neumouidae. De Haan, Nouv. Ann. du Mus. IV. PI. XVI.-XIX. 



