442 
THE INSECTA. 
§ 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 
Geocorisae, 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 veséels. 
dae and Psychodae, alone, by exception, have five.” 
The Culici- 
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, 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 
véssels 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, 
Capsus and Reduvius. With Dorthesia, the 
four canals form also two short loops; see L. Du- 
Sour, Recherch. &c. p. 19, Pl. 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 Alydus, Aradus, Aneurus; Cixvius, Issus, 
and Asiraca, they unite in twos in a common ex- 
eretory duct. With Psylla, they consist only of 
four rudimentary caeca; see £. Dufour, Recherch. 
loc. cit. 
6 It was a long time before there was an exact 
idea of the canals with Cicada. Doyér® (Ann. 
d. Sc. Nat. XI. 1839, p. 81, Pl. I.) was the first 
who perceived that they penetrated between the 
tunics of the stomach ; but he supposed they re- 
appeared on its surface after a short course. He 
did not, therefore, attribute to these insects, only 
two uriniferous vessels. This last error has been 
rectified by L. Dufour (Ibid. XII. p. 287). 
7 See L. Dufour, Ann. d. Sc. Nat, XIX. loc. 
cit. Pl. 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 Swammerdamm, Bib. der Nat. Taf. 
XLI. fig. 6 (Stratiomys) ; L. Dufour, loc. cit. Pl. 
VIII. fig. 28 (Sargus). 
9 Ramdohr, loc. cit. Taf. XX. 
10 With Pterophorus and Yponomeuta, Suckow 
has found only four uriniferous vessels (loc. cit. Taf. 
IX. fig. 159, 161). 
ll See L. Dufour, Recherch. sur les Orthopt. 
Pl. IIL.-X. ‘The smallest number of these canals 
fs found with the Formicidae, Cynipidae, and Ich- 
neumonidae. i 
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. 
18 See L. Dufour, Recherch. sur les Orthopt. 
&c. Pl. L-IV. XI. XIII. Gryliotalpa is distin- 
guished from the other Orthoptera in that the 
urinary canals are disposed fasciculate and termi- 
nate in a single excretory duct. 
oe L. Dufour, Recherch. loc. cit. Pl. XIII. fig. 
6. 
15 LZ. Dufour, Toid. Pl. 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, Stapbylinidae, Gyrinidae, Palpicornes, La- 
mellicornes, Cantharidae, and Buprestidae; six 
with the Byrrbidae, Nitidulidae, Dermestidae, 
Cleridae, Meloidae, Pyrochroidae, Bruchidae, Bos- 
tricidae, Capricornes, Chrysomelidae, and Coccin- 
ellidae. 
V7 For the uriniferous canals of the Coleoptera, 
see, beside Ramdohr, and Suckow, loc. cit., L. 
Dufour, Ann. 4. Sc. Nat. 1824, IL-IV. ; 1884, I. 
Pl. II. IfI.; 1840, XIII. Pl. V. VI.; XIV. Pl. XI.;_ 
XIX. Pl. VI. With 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. Pl. VII. fig. 7, 8, and 1844, XIX. Pl. VII. fig. 
10. 
18 Beside Ramdohr, and Suckow, loc cit., see L. 
Dufour, Ann. d, Sc. Nat. XII. 1839, Pl. I.; XIIL 
Pl. V.; and XVIII. Pl. IV. (larva of a Tipulide, a 
Sapromyza,a Pyrochroa, and of a Cetonia, &c.) ; 
De Haan, Nouy. Ann. du Mus. IV. Pl. XVI.-XIX. 
