412 



NEUROPTERA 



base, and a terminal part which is very slender and pointed, and 



formed of four or five joints. 



The prothorax is always small ; the pronotum is distinct, 



though in some forms it is quite concealed in the concavity of 



the back of the head ; the sternum is small ; the anatomy of the 



pleura and basal pieces of the legs is obscure. 



The meso- and meta-thorax are very intimately combined, 



and their relations are such that the former is placed much 



above the latter. This 

 peculiarity is carried to its 

 greatest extent in some of 

 the Agrioninae (Fig. 262, 

 A), where not only are 

 the wings placed at a 

 considerable distance be- 

 hind the three pairs of 

 legs, but also the front 

 pair of wings is placed 

 almost directly above the 

 hind pair. In the Anisop- 

 terides these peculiarities 

 are much less marked 

 (Fig. 262, B), nevertheless 

 even in them the three 

 pairs of legs are placed 

 ({uite in front of the wings. 

 This peculiar structure of 

 the wing-bearing segments 



Fig, 262. a, Agrion pulchellum, natural size ; B, is accompanied by an 

 Aeschnacyanea vrof^\e-C,^m^ from ironi to ^^^^^^^^^ development of 

 snow position of legs, g natural size. ^ ^ 



the pleura, which, indeed, 

 actually form the larger part, if not nearly the whole, of the 

 front region of the dorsal aspect of these two segments. We 

 shall not enter into more minute particulars as to the struc- 

 ture of the thorax, for difference of opinion prevails as to the 

 interpretation of the parts.^ The abdomen is remarkable for 

 its elongation ; it is never broad, and in some genera Mecisto- 

 gaster, e.g. it attains a length and slenderness which are not 



^ Reference may be made to Calvert's recent paper introductory to the study of 

 Odonata, in Tr. Amer. ent. Soc. xx. 1893, pp. 159-161. 



