II] 



EXTERNAL FEATURES AND SKELETON 



25 



precoslal (pc), the mesopleural (pl 2 ), the interpleural (ip), the meta- 

 pleural (pl s ], and the posterior epimeral (ep). The mesopleural lies 



cxm 



B 



Fig. 8 A. Internal ventral view of skeleton of a Dragonfly's thorax, to shew 

 endoskeleton. Adapted from Berlese. B. T.S. through metathoracic neural 

 canal in Isosticta simplex Martin ( x 15). Original, ac acetabulum ; cut 

 cuticle; cx 3 metacoxa; cxm coxal muscles; hy hypoderm; na sternal 

 apodemts ; ;c neural canal ; ng metathoracic gangh'on ; St metastigma. 

 For references to parts of endoskeleton, see text; to exoskeleton, legend of 

 fig. 1. 



along the humeral suture (hs), and is continued ventrally into the 

 sterno-episternal (se) directed forwards and downwards, and the 

 sterno-epimeral (se f ) directed backwards and downwards, to the 



