45 



The maxillae or under jaws are fixed immediately behind the 

 mouth, and they bear inner and outer palpi resembling lobes. 



The labium is fixed on the under side of the head, and also bears 

 palpi, which are known as labial palpi. 



The mouth parts of different insects vary considerably, according 

 to whether they are carnivorous or herbivorous; in different cases 

 certain parts are more in evidence than others. 



The thorax consists of three segments, to each of which a pair of 

 legs is fixed. 



To the second and third segments, in winged insects, a pair of 

 wings are attached, except in the order Diptera, where the hind wings 

 are very rudimentary. 



Often the hind wings are coupled to those in front by means of 

 hooked hairs, and the wings of many insects, including the order 

 Lepidoptera, are covered with scales. 



The legs of insects help very much in their classification, and 

 consist of five parts, which are : — 



The coxa, or joint by which the leg is attached to the thorax. 



The trochanter, the next joint and usually very small. 



The femur, the stoutest joint of the leg, and longer than the 

 first two. 



The tibia, the longest joint and usually very hairy. 



The tarsus or foot, consisting of from one to five segments, the 

 last joint being furnished with claws or cushions. 



The parts of the leg are often different, according to whether the 

 insect digs, springs, &c., being various parts modified according to 

 function. 



The abdomen may consist of as many as ten segments, which 

 may be movable or fixed. 



This region rarely bears any appendages, and ovipositors, forceps, 

 and bristle-like structures are the only ones borne on this part. 



The description here given is of a mature insect, as larvae and 

 pupae bear more legs, and some are borne on the abdominal segments, 

 such as the prolegs, &c. 



Metamorphoses oj Insects.— The insect always begins life as an egg, 

 except in rare cases where " budding " is resorted to in the Aphides, 

 and is not, as at one time was thought, produced by spontaneous 

 generation from dead and decaying substances. 



The eggs vary in size and shape, according to the insect, and the 

 shell may be smooth or sculptured. 



They are deposited singly or in groups, in contact with or very 

 near a sufficient supply of food for the nourishment of the young larvae, 

 and thus many insects deposit their eggs on leaves, others in stems 

 or under the bark, as will be seen. 



The number of eggs deposited by a single insect varies from twelve, 

 or even less, to fifty thousand, most insects laying from fifty to one 

 hundred and twenty. 



After a time, a tiny creature comes forth known as the larva, 



