The Nymph. 



39 



three lamellae are marked c.l. When nearing maturity the 

 sex of the Dragonfl\--in'mph may be distinguished in 



Fig 



-Vk.ntral Surface Fig. iS. — Vkntral Sirface 



OF Ninth Segment of 



XVMPH OF ANAX IMPERA- 



•loK (Male). 



(Much nugnified.) 



OF Ninth Segment of 

 Nymph of Anax impera- 

 tor (Female). 



(Much magnified.) 



Fig. 19. — Leg-base Processes of various ^F^schnine Dragonflies. 



1. Anax imperator. 



2. Brachytron pratense. 



3. ^tsCHNA MIXTA. 



4. /ESCHNA JUXCEA. 



5. /ESCHNA CYANEA. 



6. ^SCHNA GRANDIS. 



7. /Eschna isosceles. 

 (3, 4, 7, after Cabot.) 



some species at least. It hes in the difference between 

 a pair of valves on the underside of segment 9 

 (Figs. 17 and 18), and in the presence, in the males 



