98 



THE REPORT OF THE 



No. l*y 



gions, head, thorax, and abdomen; they breathe air; they have one pair of 

 feelers, or antennae; and usually one or two pairs of wings. By these char- 

 acters, insects are readily distinguished from true worms, or from spiders, 

 certipedes, and cray-fish, their near relatives. 



llie Head. The head bears the feelers or antennae, the eyes, and the 

 mouth-parts, and is concerned with the sensation of touch and the getting 

 of food. 



The feelers function as organs of touch and perhaps of taste, and are very 

 varied in shape. The eyes are compound and are composed of a large num- 

 ber of simple eyes. The mouth-pfirts are very unlike in different insects. 

 In those insects which feed by chewing or biting their food, there are an 

 upper lip, the labruTn; a pair of jaws, the mandibles, which work sideways; 

 a pair of smaller jaws, with feelers, the maxiUcc ; and a lower lip, the lahium 

 (Fig. 17). In those which take up fluid food, the mouth-parts are modified 

 for sucking (Fig. 18), licking or piercing (Fig. 19). To combat injurious 



Fig. 19. 



Head ux a sucking inssect (Squash bug) ; a antennw ; l> the eye ; c the4-jointeil Ijeak 

 dand e the four lances ;/the labrum, (original). 



insects successfully, the farmer or gardener should be able to tell biting 

 forms from sucking forms, for it is possible to poison the food of the former, 

 but not that of the latter. 



The Thorax. The thorax is composed of three united segments. The 

 liist bears a pair of legs, while the second and third bear not only a pair of 

 legs, but also often a pair of wings. It is clear that this region of the body 

 is concerned with movement. (Fig. 20). 



The legs of insects are jointed, and are composed of the following parts : 

 The coxa, or hip; the trochanter ; the femur, or thigh; the tibia, or shank; and 

 the tarsus, a three to five jointed foot ending in claws. (Fig. 17). 



The Abdomen. The abdomen. is composed of many segments without 

 limbs in adults; but in the young state, some insects, such as, butterflies, 

 moths, saw-flies, there are unjointed feet, or pro-legs, on the abdomen, 

 (Fig. 21). The organs of reproduction and digestion are situated within the 

 abdomen. 



The alimentary canal occupies the middle portion of the body, and is 

 composed of gullet, crop, gizzard, stomach, and intestine. The crop may be 

 (ailed the storing stomach, and the gizzard the grinding stomach. Digestion 

 takes place in the true stomach, into which the coecal tubes empty their se- 

 cretions. With most sucking insects, however, the gizzard is wanting. 



