PLATE XVIII. 



RANATRA AND NEPA. 



Fig. 1. Ventral view of the tip of abdomen of female Ranatra. Note 

 the narrow carinated ventral plate. 



Fig. 2. Ventral view of tip of abdomen of male Ranatra. Note broad 

 ventral plate. 



Fig. 3. Enlarged egg of Ranatra. Note micropylar area near the 

 base of the filaments. 



Fig 4. Ventral view of head and prothorax of Ranatra to show 

 tonal device. (See, also, figure 9.) The inner margin of the prothoracic 

 shoulders (b) is roughened by a series of tiny ridges over which a 

 roughened patch (a) on the outside of the coxa rubs. 



Fig. 5. Fore leg of Ranatra. 



Fig. 6. The cephalic end of a Ranatra egg, showing the post-natal 

 molt and the rent in the egg shell through which the nymph emerged. 



Fig. 7. Fore leg of Nepa. 



Fig. 8. Cephalic end of Ranatra egg, side view. Note the micro- 

 pyle (m). 



Fig. 9. Tonal device of Ranatra, (c) coxa outside view, with rougened 

 patch (a). Shoulder of prothorax with rasp (?•) along its inner mar- 

 gin. (See figure 4.) 



Fig. 10. Hydrachnid larva attached to caudal filament of Ranatra, 

 thus making the tube nonfunctional to this point. 



Fig. 11. Ventral view of abdominal tip of female Nepa. 



Fig. 12. Egg of Nepa apicidata. Note that there are eleven filaments 

 in our species. The European form has long been described as possess- 

 ing seven. 



Fig. 13. Ventral view of abdominal tip of male Nepa. Compare with 

 figure 11. 



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