346 INSECTA. 



with them are named Coleoptera, and in such they are never absent t 

 though this is sometimes the case with respect to the wings. In 

 other Insects the extremity of the scale is completely membranous, 

 or like the wing: they are styled Hemiptcra. 



The scutel or scutellum is usually a small triangular piece, situa- 

 ted on the back of the mesothorax, and between the insertions of 

 the elytra or of the wings. Sometimes it is very large, and then it 

 covers the greater part of the superior portion of the abdomen. In 

 various Hymenoptera, behind the scutellum and on the metathorax, 

 we find a little space called the post- scutellum. 



The ambulatory organs of locomotion consist of a coxa formed of 

 two pieces, a femur, an uniarticulated tibia, and of a tarsus, which 

 is divided into several phalanges. The number of its articulations 

 varies from three to five, a difference which greatly depends upon 

 the proportional changes experienced by the first and penultimate 

 joints. Although their supputation may sometimes prove embar- 

 rassing, and this numerical series may not always be in exact accord- 

 ance with the natural order, it furnishes a good character for the 

 distinction of genera. The last joint is usually terminated by two 

 hooks. The form of the tarsi is subject to some modifications, ac- 

 cording 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 In- 

 sects, or those which have but six feet, it is distinct. It contains 

 the viscera, &c., presenting nine or ten segments or annuli, some 

 of which, however, are frequently concealed or considerably reduced. 

 The last annuli of the abdomen, in several females, form a retrac- 

 tile or always projecting ovipositor more or less complicated, which 

 acts like an auger. A sting is substituted for it in many of the fe- 

 male Hymenoptera. The female 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 

 them. This maternal solicitude often excites our surprise, and more 

 particularly unveils the instinct of Insects. In the numerous socie- 

 ties of several of these animals, such as the Ant, Termes, Wasp, 

 Bee, &c., those individuals which form the greater portion of the 

 community, and by whose labour and vigilance the whole cornmu- 



