ODONATA 57 



II. In the thorax. 



1. The small prothorax, tapering forward into a small 

 stalk, that loosely supports the head. 



2. The large side pieces of the synthorax, expanded to 

 meet in front of the wings above, and behind the legs 

 below. This is the "housing" of the immense wing 

 muscles of these strong flying insects. 



3. The two pairs of spiracles of the synthorax; one above 

 the base of the middle leg and the other at the front 

 partially concealed by the overlapping margin of the 

 prothorax. 



4. The position of the legs and the direction of the spines 

 on them: in flight these are so carried as to form a 

 big basket, that is thought to be useful in capturing 

 prey — bagging it, so to speak, as in a net. 



III. In the abdomen. 



1. The pair of infolded longitudinal furrows along the 

 sides. The abdominal spiracles are in these furrows, 

 which expand, bellows-like, with the respiratory move- 

 ments. 



2. The swollen region about the 2nd and 3rd segments. 

 In the male there is a special development of copulatory 

 apparatus underneath these segments that is another 

 peculiarity of this order of insects. 



3. The short appendages at the end of the abdomen, 

 longer and clasperlike in the male. Beneath the tip 

 of the abdomen of the female there is a flat ovipositor 



