HEAD AND THORAX 



But if we observe the head of a squash bug, we find no jaws or other 

 parts that would serve to chew or bite. Instead there is a stout beak, 

 and if we were to dissect this, we should 

 find that it contained a tube for sucking 

 ui) plant juices or other fluids.. In ad- 

 dition, we should fuid in most insects of 

 this type, two or three pairs of lancets within 

 or close to the beak, used to punctui'e or 

 rasp the tissues so as to induce a greater 

 flow of the 

 juices. 



Insects with 

 biting mouth 

 parts may be 

 killed by cov- 

 ering the plant 

 on which they 

 feed with a 

 poison, such as 

 lead arsenate. 

 But insects 

 with sucking 

 mouth parts 

 do not eat the surface of the plant and cannot be killed by applica- 

 tions of stomach poison. For the latter other remedies must be 

 used, such as some substance that will kill the insect by corrosive 

 action on its body. 



The Thorax 



The middle part of an insect's body is called the thorax. Usually 

 it has three distinct rings, or segments. On each segment is a pair 

 of legs and on each of the last two is a pair of wings, except in the 

 group of two-winged flies, which have only a single pair, on the middle 

 segment. 



An insect's leg consists, tj'pically, of a small joint next the body, 

 the trochanter; a large and heavy joint, the femur; a slender tibia; 



Fig. 



6. — Mouth parts of 

 a honeybee. Enlarged. 

 Original. 



Fig. 7. — Mouth parts of a 

 horsefly, fitted for pierc- 

 ing and sucking. Enlarged. 

 Original. 



