INSECTS. 13 



The Body in the major part of Insects is divid- 

 ed into the thorax or upper part, and the abdo- 

 men or lower part. In many of the Beetle tribe 

 the back of the thorax is distinguished by a small 

 triangular piece or division, situated at its lower 

 part, between the juncture of the wing-sheaths : this 

 triangular part is termed Scutdlum or escutcheon. 

 The under part of the thorax is called the breast, 

 or Pectus, and in this the sternum is frequently 

 distinguishable. The abdomen is marked into 

 transverse sections, and the last joint terminates 

 in the tail, or pointed extremity. The wing- 

 sheaths or shelly coverings, in the Beetle tribe 

 and some others, are termed Elytra or Coleoptra. 



The Limbs, in the major part of Insects, consist 

 of three principal di visions ; viz. the upper joint, 

 Femur or thigh, the second joint, Tibia or leg, and 

 the third, Tarsus or foot, which commonly consists 

 of several small articulations, and is terminated 

 by a dilated tip, with t\vo hooked claws. 



In many Insects there are two small parts re- 

 sembling minute bladders, fixed on a slender, 

 short stem, and situated one under each wing: 

 these parts are called Halteres, balancers, or 

 poisers, and are only to be found in the two- 

 winged insects: their supposed use is to keep the 

 Insect steady during its flight, since if one of 

 them be cut off, the animal flies with an unsteady 

 motion. 



The majority of Insects are observed to be an- 

 nual; finishing the whole term of their lives in 

 the space of a year or less; and many do not live 



