442 



THE IXSECTA. 



^^ 346. 



of the Geocorisae.''* With some species, their excretory ducts form one or 

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

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

 free.''" With this last group, and with the Cercopidae, 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 uriniferous vessels. The Culici- 

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

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

 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, which 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 ofteu 

 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, 

 Capsus and Redttviu.i, Witli Dorthesia, tlie 

 four canals form also two short loops ; see L. Du- 

 fouT, Recherch. &c. p. 19, PI. I.-IX. 



4 Pentatoma, Tetyra, Pyrrhocoris, Lygaeus, 

 Gerris, Stenocephalus. 



5 Cimex, Ploiaria, Miris, Alydus and Coreus. 

 In the last two genera the uriniferous canals, free, 

 terminate at the pylorus in a common reservoir. 

 With A/ydus, Aradus, Aneurus; Cixiu.i, Issus, 

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

 cretory duct. With Psy/ta, they consist only of 

 four rudimentary caeca; see L. Du/our, Kecherch. 

 loc. cit. 



6 It was a long time before there was an exact 

 idea of the canals with Cicada. Doyire (Ann. 

 d. Sc. Nat. XI. 1839, p. 81, PI. I.) was the first 

 who perceived that they penetrated between the 

 tunics of the stomach ; but he supposed they re- 

 appeared Oil its surface after a short course. He 

 did not, therefore, attribvite to these insects, only 

 two uriniferous vessels. This last error has been 

 rectified by L. Dufour (Ibid. XII. p. 287). 



^ See L. Dufour., Ann. d. Sc. Nat. XIX. loc. 

 cit. PI. VIII. fig. 26 (^Anopheles). 



8 With the Muscidae, Oestridae, Conopidae, 

 Syrphidae, and Hippoboscidae. With the Stratio- 

 mydae, the four canals unite Into one excretory 

 duct ; see Swammerdarnrn, Bib. der Nat. Taf. 

 XLI. fig. 6 (Strntiomus) ; L. Dufour., loc. cit. PI. 



VIII. fig. 28 {Sargux). 



'•I Hamdohr, loc. cit. Taf. XX. 

 lU With Pterop/iorus and Yponomeuta, Suckow 

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



IX. fig. 159, 161). 



11 See L. Dufour, Recherch. sur les Orthopt. 

 PI. III.-.X. The smallest number of these canals 

 is found with the Formicidae, Cynipidae, and Ich- 

 aeumuuiduc. 



12 With the Ephemeridae, alone, the form of 

 these canals is somewhat different, in that their free 

 extremities are nearly always thickened, and that 

 the Excretory ducts take one or two spiral turns. 



13 See L. Dufour, Recherch. sur les Orthopt. 

 &c. PI. I.-IV. XI. XIII. Gryllotalpa is distin- 

 guished from the other Orthoptera in that the 

 urinary canals are disposed fasciculate and termi- 

 nate in a single excretory duct. 



. 1-f L. Dufour., Recherch. loc. cit. PI. XIII. fig. 

 196. 



15 L. Dufour, Ibid. PI. XI.-XIII. There are 

 six of these vessels with the Phryganidae, Sialidae, 

 Panorpidae, Rhapididae : and eight with the Myr- 

 meleonidae and Hemerobidae. 



16 There are four urinary vessels with the Cara- 

 bidae, Staphylinidae, Gyrinidae, Palpicornes, La- 

 mellicornes, Cantharidae, and Buprestidae ; six 

 with the Byrrhidae, Nitidulidae, Dermestidae, 

 Cleridae, Meloulae, Pyrochroidae, Bruchidae, Bos- 

 tricidae, Capricornes, Chrysomelidae, and Coccin- 

 ellidae. 



17 For the uriniferous canals of the Coleoptera, 

 see, beside Ramdolir, and Suckow, loc. cit., L. 

 Dufour, Ann. d. Sc. Nat. 1824, II.-IV. ; 1834, I. 

 PI. II. III.; 1840, XIII. PI. V. VI.; .XIV. PI. XI.; 

 XIX. PI. VI. M'ith Donacia, the six vessels 

 have a very peculiar aspect. Two pairs unite 

 loop-like at their posterior extremities, and their 

 anterior ends unite in a common reservoir ; while 

 the third pair are free and open isolately at the 

 pylorus ; see L. Dufour, Ann. d. Sc. Nat. 1824, 

 IV. PI. VII. fig. 7, 8, and 1844, XIX. PI. VII. fig. 

 10. 



18 Beside Ramdnhr, and Suckow, loc cit., see L, 

 Dufour, Ann. d. Sc. Nat. XII. 1839, PI. I.; XIII. 

 PI. v.; and .Will. PI. IV. (larva of a Tipulide, a 

 Snpromyza, a Pyrnchron, and of a Cetnnia, &c.) ; 

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



