NEUROPTERA. 165 



Fig. I. represents the Labium of Libeliula. 



L. The Labium proper, formerly called the middle 



lobe of lower lip. 

 P. The Palpi, formerly called the lateral lobes of 

 lower lip. 

 Fig. II. represents the extremity of the abdomen of a Cor- 

 dulia $ , seen obliquely. 



10 is the last dorsal segment. 

 z z the upper anal appendages. 

 y y the lower anal appendages. 

 Fig. III. represents the extremity of the abdomen of 

 Agrion 2 , side view. 



10 is the last dorsal segment. 

 z is the tentacula. 

 Y is the vulvar scale. 

 Fig. IV. represents the hind wing of Cordulia cenea, with 

 the course of the principal nervures only expressed. 

 X is the anal angle. 



m is the accessory membrane (the stippled space). 

 3, 4, 5, 6, 8, 9 are main nervures, called " Sectors." 



1 is the costal nervure. 



2 and 7 are the main nervures, called " Radii." 



2 is radius principalis. 

 7 is radius medius. 

 5 is the subnodal sector. 

 C is the cubital point. 



a — a are the ante-cubital nervures (transverse). 

 s is the Pterostigma. 

 e is the triangle. 



P is the post-trigonal area (included between the 

 radius medius 7, and the sector 8). 

 The term "adult" used in several of the descriptions arises 

 from the fact that these insects are often many days on the 

 wing before they get the mature colour. 



