8 
INTRODUCTION. 
corresponding, for the most part, in situation, with the ears 
ot other animals, and supposed to be connected with the 
sense of hearing, of touch, or of both united. The antennae 
are very short in larvae, 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 arid 
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. I he former are two or four in number, and vary 
greatly in form and consistence, in the situation of the wing- 
hones 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 
