4 LIFE STORIES OF AUSTRALIAN INSECTS. 



tube formed by the closely adpressed setae or sty- 

 lets. There is a sheath present to enclose the 

 stylets. 



II. The Thorax is the 2nd division of the body: 

 and is made up of three more or less distinct seg- 

 ments known respectively as (a) prothorax, (b) 

 mesothorax, (c) metathorax. In some insects these 

 are fused so that one can not distinguish the seg- 

 ments. 



The prothorax carries the ist pair of legs; the 

 mesothorax the ist pair of wings and the 2nd pair 

 of legs; the metathorax, the 3rd pair of legs and 

 the 2nd pair of wings. 



The leg of an insect can be divided into 5 dis- 

 tinct parts (Plate 2, Fig. i): (i) The coxa or hip; 

 (2) the trochanter (usually very small); (3) the 

 femur, or thigh (4) tibia, or shank; (5) tarsus, or 

 foot, which has usually 5 joints, the last joint carry- 

 ing claws and sometimes a pad also, called the pul- 

 villus. (Plate 2. Fig 2 a, b.) 



Wings. — Wings differ according to the different 

 orders, but broadly speaking they are more or less 

 triangular in shape and usually membranous, sup- 

 ported by thickened lines called veins. The arrange- 

 ment of the veins varies also. Dipterous insects 

 (flies, mosquitoes, etc.) and a few others have but 

 2 wings, the hind pair of wings being absent; in 

 their place is a pair of knobbed processes called 

 halteres or balancers. (Plate 42, Figs. 2, 8.) Some 

 insects have no wings, as fleas and silverfish. 



III. Abdomen. — This is the third and terminal 

 division of the body, and is made up of ringed 

 segments, sometimes 9 or 10 in number, but the 



