ANNULOSA. 535 



aerate this mass ; and that, while the dorsal vessel and the 

 peritoneal membrane prepare fat, the hepatic filaments se- 

 parate from it bile, and probably urine. The existence of 

 this last excrementitious fluid, is evinced by the presence 

 of urea in the excrement. The peculiar secretions are 

 nowise remarkable *. 



The pedate annulosa have the sexual organs on diffe- 

 rent individuals ; impregnation takes place internally by 

 their union, and the females are all oviparous. 



In the male, the sexual organs bear a closer resemblance 

 to those of the mammalia than some of the higher classes. 

 The testes may be regarded as two in number, situate one 

 on each side of the abdomen. In some cases, however, 

 they appear a simple mass, while in others, they are sub- 



" All those insects which live in society, when exposed to cold, are ob- 

 served to cluster together as if to keep each other warm. Some, indeed, 

 when exposed to cold become torpid, and revive upon the restoration of a 

 suitable temperature ; but there are others, as the honey-bee, which resist 

 any reduction of their temperature below their ordinary digestive heat, and 

 preserve it in their dwellings even during the winter season. John Hunter 

 found a hive in July 18. at 82°, when the temperature of the air was only 

 54°, and in December 30. at 73°, when the air was 35°. (Phil. Trans. 

 1792, 136.) When cooled until they become benumbed, they seldom recover, 

 while the wasp, belonging to the same natural order, can be rendered torpid, 

 and again revived with safety. 



There is one circumstance recorded, which ought to excite inquiry, in 

 hopes of finding in insects electrical organs similar in their effects to those 

 of the torpedo. It refers to the Reduvius serratus, commonly known in 

 the West Indies by the name of the Wheel-bug. '• The late Major-general 

 Davies, of the Royal Artillery, well known as a most accurate observer of 

 nature, and an indefatigable collector of her treasures, as well as a most ad- 

 mirable painter of them, once informed me, that when abroad, having 

 taken up this animal and placed it upon his hand, it gave him a consider- 

 able shock, as if from an electric jar, with its legs, which he felt as high as 

 his shoulders, and, dropping the creature, he observed six marks upon his 

 hand where the six feet had stood." (Kirby and Spence's Introduction to 

 Entomology, vol. i. p. 110.) 



