338 
INSECTA. 
joints. Altliougli their snpputation may sometimes prove embarrass- 
ing, and this numerical series may not alwaj's be in exact accordance 
with the natural order, it furnishes a good character for the distinc- 
tion of genera. I’he last joint is usually terminated by two hooks. 
The form of the tarsi is subject to some modilications, according to 
the habits of the animal. Those of aquatic species are usually 
strongly ciliated and flattened, and resemble oars 
The abdomen, which forms the third and last part of the body, is 
confounded in the Myriapoda, with the thorax : but in all other 
Insects, or those which have but six feet, it is distinct. It contains 
the viscera and the sexual organs, presenting nine or ten segments or 
annuli, some of which, however, are frequently concealed or con- 
siderably reduced. The organs of generation are situated at the 
posterior extremity and issue through the anus. The luli and 
Libellulse alone constitute exceptions. The last annuli of the abdo- 
men, in several females, form a retractile or always projecting 
ovipositor — oviscapte of Marcel de Serres — more or less complicated, 
which act as an auger. A sting is substituted for it in many of the 
female Hymenoptera. The fecundating organ of the male is almost 
provided with hooks or a forceps f. The sexes usually copulate but 
once, and this junction in certain genera is even sufficient for the 
fecundation of several successive generations. The male places 
himself on the back of his mate, and remains there for some time. 
The latter soon lays her eggs and deposits them in the way best 
adapted for their preservation, and in such a manner that the moment 
the larvae make their appearance, suitable aliment is always within 
their reach. " Frequently she collects provisions for tliem. This 
maternal solicitude often excites our surprise, and more particularly 
unveils the instinct of Insects. In the numerous societies of several 
of these animals, such as the Ant, Termes, Wasp, Bee, &c., those 
* M. Kirby, in his Monograi)h of the Bees of England, designates the two 
anterior tarsi by the name of hands. The first joint is the jjaha, — palma. This 
gentleman, in conjunction with M. Spence, has published a very complete and 
detailed work on the elements of Entomology. 
t The generating organs of the male consists of an apparatas for the elabora- 
tion of the semen, and of the parts proper to copulation. The preparatory ap- 
pai-atus is composed of testes, vasa deferentia, and vesiculse seminales. The copu- 
lating instrument is a penis provided with an armature consisting of surrounding 
parts, of various forms, acting like pincers or forceps, with which the male seizes 
the posterior extremity of the body of the female. The sexual apparatus of the 
latter is composed of an ovary, the receptacle or calyx formed by its base and the 
oviduct. For more minute details, see the memoirs of M. Dufour, Ann. des Sc. 
Nat., and the Dissertation of Hegetschweiler, Zurich, 1820 . 
+ M. Audouin supposes, that, in a great number of Insects, the ova are fecun- 
dated, as they descend, in a sac situated near the anus ; but this idea requires to be 
confirmed by experiment, and one of those naturalists who have most closely studied 
the anatomy of these animals, M. Dufour, is of a different opinion. 
