83 



A. Three pairs of lateral spines, all well-developed; eyes 

 occupying at least two thirds of the side margin of the 

 head ; scale of male on base of superior appendage short 

 and broad, emarginate at apex ; apical emargination of 

 superior appendage about as in jEscJuia. VI. Anax. 



I. Nasi^schna Selys. 



The single species which follows has until recently re- 

 mained in the genus .-E.srJina, but it is very evidently gener- 

 ically distinct from all other American .^Jsrlniifhr, and has, in 

 fact, been lately so recognized by Selys-Longchamps and E'ors- 

 ter under the name of Nas.iceschna.'^ It has been referred by 

 Hagen (77, p. 37) to BrftcJii/froii Evans, but it is intermediate be- 

 tween that and Ep'uesclina Hagen. Aside from secondary sexual 

 characters, it is nearer the latter genus. The following char- 

 acters sufficiently distinguish the imago from related genera: 



Face concave ; frons narrow, produced above into a shelf- 

 like prominence, with a broad longitudinal superior furrow, and 

 without "T" spot. Radial (subnodal) sector forked midway 

 between the nodus and the middle of the stigma, the branches 

 of the fork diverging all the way to the wing-margin ; first and 

 second branches of media (principal and nodal sectors) not ap- 

 proximated beyond the fork of the radial sector ; apical sector 

 originating near the anterior end of the stigma ; anal loop ovab 

 lying nearly lengthwise of the wing, with about two longitudi- 

 nal rows of cells, usually one cell between bases of the 2d and 

 3d anals ; supratriangular space with two or three cross-veins, 

 triangles 3- or 4-celled, inner side not receiving a cross-vein. 

 Inferior abdominal appendage of male hardly shorter than 

 superiors. 



Epimchia dehilis Karsch (Ent. Nachr., Vol. XVII., p. 286) 

 perhaps belongs to this genus. 



The nymph of Na^kesclina differs from all other asschnids 

 in the possession of dorsal hooks. Our species represents a dis- 

 tinct and primary step in the evolution of the ^Eschnida', and 

 its claim to generic distinction is beyond question. 

 ♦See "Ent. News," Vol. XI., p. 546. 



