40 SYNOPSIS OF SPECIES DESCRIBED. 



incuts are small blunt tubercles, indicated only on 4th ; lateral spines on 8th and 

 9th segments flat, sharp, iueurvate; ventral edge of 9th fringed with long hairs. 



15. E. cynosura Say. ( liaised.) 



Nyinpha skins, male and female. New England. 



Body elongate, naked; two small tubercles behind the suture of the head; abdo- 

 men narrow, a little enlarged in the middle; dorsal hooks on 3d to 9th segments, the 

 first three spine-like; lateral spines of 8th very short, of 9th long, sharp, divergent, 

 much longer than the append i 



16. E. semiaquea Burmeister. (Supposition.) 



Xvmpha skins of male and female. New England. 



\ ■ iv similar to E. cynosura; tubercles of the head nearly absent; lateral spine on 

 9th segment only a little longer than the appendages. Perhaps this species is only a 

 variety of E. cynosura. 



17- E. species ignota 



Dry uymphse, not full-grown. Kanagawa, Japan. 



Body naked : head flat above ; two blunt tubercles in the middle ; abdomen un- 

 usual, truncate at tip, sides parallel, bulging in the basal half; dorsal hooks on 4th to 

 9th segments ; lateral spiues on 8th very short, as long as the segment on 9th. 



Cordulia Leach. (Raised.) 



Body longer, subcylindrical ; dorsal hooks absent or less developed ; lateral spines 

 very short. 



18. C. metallica Vander Linden, (liaised.) 



Xvmpha skins of male and female, and full-grown nympbae. Europe. 



Body oblong, truncate at tip, nearly naked; head short, half as long as broad, 

 slightly rounded in front ; undulated transversal crest behind the eyes with a comb of 

 tine bristles; abdomen oblong, roof-shaped, segments 8th and 9th sloping, the last trun- 

 cate ; 10th very short ; dorsal hooks on 3d to 9th, spine-like, the last three more bent 

 at tip; lateral spines on 8th and 9th, short, sharp; on 9th a little longer, the tip bent 

 inwards ; appendages short. 



19. C. eenea Linne. (Raised.) 



Nympha skin of male and female, and full-grown nymphse. Europe. 



Very similar to C. metallica ; occiput roughened, with some oval spots without 

 spines ; dorsal hooks on 3d to 9th segments thicker, only indicated on 9th ; appendages 

 shorter. 



