The Iiiias^o. 



51 



Thoui^rh possessing considerable differences there is a 

 great general resemblance between the wings of 

 Dragonflies. The main nervures all have a sub-parallel 

 direction, and these are joined by a large number of 

 small transverse nervures, 

 producing an intricate ^ y 



meshwork of cells. In 

 one division, the Aiiis- 

 optcridcs, forming the 

 families Libcllulidic and 

 ^-Esc/ii/ida\ the hind-wings 

 are larger and different in 

 shape from the fore-wings. 

 In the other division, the 

 Zygoptcrides, forming the 

 family Agrionidcc, the 

 wings are similar and 

 nearly equal. The shape, 

 size, and colour of the 

 pterostigma and accessory 

 membrane, the conforma- 

 tion of the triangle, the 

 number of ante-cubital 

 nervures, and the colour 

 of the costa, are important 

 points in classif)-ing the 

 genera and species. 



On reference to Fig. 24, A, B, and C, it will be 

 noticed that five longitudinal nervures terminate at the 

 base of the wing ; these are, starting at the front 

 margin, the costa, sub-costa, median, sub-median, and 

 post-costa. The costa and median extend to the tip 



E 2 



Yii\ 



-D(>K.SAL VIEW OF 

 lMAGf>. 



A: c, Eye; /., Frons ; v.. Vertex; an.. 

 Antenna; o., Occiput; />., Prothoiax ; /., 

 Thorax; ;;is.;;., Meso-notum ; int.it., Meta- 

 notum ; an., Auricle; i-io, Segments ol 

 Abdomen ; n.a.a.. Upper Anal Append- 

 ages ; I. a. a., Lower Anal Appendage. 



B: 8-1 1. Distal Segments of Abdomen 

 of Female ; a. a.. Anal Appendages. 



