ODONA TA 



321 



Family LIBELLULID^ 



The Ltbellulids or Skimmers 



In this family the triangle in the hind wing is much nearer the 

 arculus than is the triangle of the fore wing ; and there is no oblique 

 brace-vein extending back from the inner end of the stigma, as in 

 the ceschnids. 



This is a large family including many of our commonest and 

 best-known species of dragon-flies; many of them are familiar figures 

 flying over ponds and ditches and by roadsides. Most of them are 

 of well-sustained flight, and are seen continually hovering over the 

 surface of still water; this suggested the common name skimmers 

 which has been applied to them. 



Fig- 367. — A damsel-fly. 



Suborder ZYGOPTERA* 

 The Damsel-Flies 



The damsel-flies differ from the 

 dragon-flies in that the two pairs 

 of wing:s are similar in form and 

 are either folded parallel with the 

 abdomen when at rest (Fig. 367) 

 or uptilted (Testes). The head is 

 transverse, each eye being borne 

 by a lateral prolongation of the 

 head. The females possess an 

 ovipositor by means of which the 

 eggs are placed in the stems of 

 aquatic plants, sometimes beneath 

 the surface of the water. 



The name of the suborder 

 probably refers to the fact that 

 the wings are brought together 

 when at rest. 



Fig. 368. — Wing of Lestes rectangularis : 0, oblique vein; br, the bridge. 



''Zygoptera: zygon (,^vy6v), yoke; pteron {irrepdv), a wing. 



