PART II: TAXONOMY 



Key to Suborders 

 Nymphs 



I. Nymphs with three caudal tracheal gills attached to the tip of 

 the abdomen, consisting of flat plates traversed by tracheae 



Zygoptera, p. 35 

 Nymphs without caudal tracheal gills, usually with small spinose 

 appendages at the tip of the abdomen Anisoptera, p. 115 



Adults 



I. Front and hind wings nearly similar in shape, their greatest width 

 nearly or quite the same; anal appendages of the male always 

 four in number, two superior and two inferior ...Zygoptera, p. 35 

 Front and hind wings not at all similar in shape ; greatest width 

 of the hind wings more than the greatest width of the front. 

 Anal appendages of the male usually three in number, two 

 superior and a single broad inferior' Anisoptera, p. 115 



Suborder Zygoptera Selys 



Zygoptera or damsel flies may be recognized by their delicate 

 form, the abdomen being slender in proportion to the rest of the 

 body. Their flight is slow and uncertain because of the lack of 

 rigidity in their wings, owing to the presence of few cross-veins. 

 When at rest, the wings are held vertically, except in the genus 

 Lestes, the species of which alight with half-open wings. 



The nymphs are also slender in form, and possess long flattened 

 tracheal gills attached to the tip of the abdomen. 



Key to Families 



Nymphs 



I. Lateral gills triquetal or three-sided; first antennal segment as 



long as the remaining segments together . . . . AGRIONIDAE, p. 108 

 Lateral gills flat, not three-sided; first segment of the antennae 



shorter than the remaining segments together 



COENAGRIONIDAE, p. 35 

 Adults 



I. Interpleural suture well developed (distinct as far cephalad as the 

 metathoracic spiracle and usually visible beyond this point) ; 

 bright metallic colors frequently present ....AGRIONIDAE, p. 108 

 Interpleural suture only partly or not at all developed; bright 

 metallic colors rarely present COENAGRIONIDAE, p. 35 



Family COENAGRIONIDAE Kirby 



The nymphs have only flattened tracheal gills and the mentum 



is never cleft as far proximad as the articulation of the labial palpi. 



Adults of this family are frequently marked with bright blue or 



" According to Crampton, the inferior appendage of Anisoptera is not homologous 

 to the inferiors of the Zygoptera. See Bull. Brooklyn Ent. Soc. 13: 49-68: 191 8, pis. 2-7. 



