8 INTRODUCTION. 



corresponding, for the most part, in situation, with the ears 

 of other animals, and supposed to be connected with the 

 sense of hearing, of touch, or of both united. The antennae 

 are very short in larva?, and of various sizes and forms in 

 other insects. 



The mouth of some insects is made for biting or chewing, 

 that of others for taking the food only by suction. The 

 biting-insects have the parts of the mouth variously modified 

 to suit the nature of the food ; and these parts are, an upper 

 and an under lip, two nippers or jaws on each side, moving 

 sidewise, and not up and down, and four or six little jointed 

 members, called palpi or feelers, whereof two belong to the 

 lower lip, and one or two to each of the lower jaws. The 

 mouth of sucking-insects consists essentially of these same 

 parts, but so different in their shape and in the purposes for 

 which they are designed, that the resemblance between them 

 and those of biting-insects is not easily recognized. Thus 

 the jaws of caterpillars are transformed to a spiral sucking- 

 tube in butterflies and moths, and those of maggots to a 

 hard proboscis, fitted for piercing, as in the mosquito and 

 horse-fly, or to one of softer consistence, and ending with 

 fleshy lips for lapping, as in common flies ; while in bugs, 

 plant-lice, and some other insects resembling them, the 

 parts of the mouth undergo no essential change from infancy 

 to the adult state, but are formed into a long, hard, and 

 jointed beak, bent under the breast when not in use, and 

 designed only for making punctures and drawing in liquid 

 nourishment. 



The parts belonging to the thorax are the wings and the 

 legs. The former are two or four in number, and vary 

 greatly in form and consistence, in the situation of the wing- 

 bones or veins, as they are generally called, and in their posi- 

 tion or the manner in which they are closed or folded when 

 at rest. The under-side of the thorax is the breast, and to 

 this are fixed the legs, which are six in number in adult 

 insects, and in the larvae and pupae of those that are subject 



