598 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



EXPLANATION OF PLATE 115. 

 The drawings are by the author. 



Figs. 1-7. — Progomphus obscurus.—l, mature naiad; 2, antenna of mature naiad; 

 3, lateral labial lobe of mature naiad; 4, antenna of young naiad; 5, lateral labial lobe 

 of young naiad; 6, a portion of the armature of the median labial lobe, showing the 

 two triangular teeth; 7, abdomen of young naiad, showing the armature. 



Figs. 8-12. — Gomphus (Arigomphus) , species ? — 8, naiad; 9, labial armature; 10, 

 head; 11, labium; 12, segments 7-10 of the abdomen. 



