Plate LIX 

 Nympluil Structures 



Fi<^. 14. Lcstcs rectavguldris, wing-case. 



Fig. 15. Hetaerina (imcricuna, wing-ease. 



Fig. 16. Enallagma signatum, wing-ease. 



Fig. 17. The same, young nymph, Aving-case. 



Fig. 18. Isclinura verticalis, eaudal end of the abdomen 

 with the two lateral gills removed. 



Fig. 19. Enallagma exsulans, tarsus. 



Fig. 20. The same, leg. 



Fig. 21. Isclinura verticalis, dorsum of meso- and 

 metathorax. 



Fig. 22. Agrion ynaculatum, maxilla. 



Fig. 23. Hetaerina americana, dorsum of the prothorax. 



Fig. 24. Isclinura verticalis, ventral aspeet of thorax 

 and cephalic segments of abdomen. 



Fig. 25. The same, lateral aspeet of thorax and ab- 

 domen. 



Fig. 26. Enallagma sp., cross-section of gills. 



