126 



EXPLANATION OF PLATE. 



1. Argia trandata Hagen. Ohio Pyle, Pa., September 8, 1901, J. L. Graf. 



Lateral view of (^ abdominal appendages. 



2. Herpetogonvphus designatm Hagen. Portion of right wing; t, triangle; i, in- 



ternal triangle ; a, anal vein (or postcosta); b, first branch of anal vein ; 

 c, second branch of anal vein ; p, post-anal cells (middle post costal 

 space). 



3. Ophiogomphus rupinsidensis Walsh. Portion of right wing. Lettering same 



as for fig. 2. 



4. Gomphus spicatus Hagen. Portion of right wing. Lettering same as for 



fig. 2. 

 -5. Gomphus viUosipes Selys. Portion of right wing. Lettering same as for 

 fig. 2. 



6. Gomphu?, scudderi Selys. Portion of right wing. Lettering same as for 



fig. 2. 



7. Lanthus alhistylus Selys. Portion of right wing. Lettering same as for 



fig. 2. 

 8 and 9. EnaUagvia douhkdayi Selys. Provincetown, Mass., August 4, 1899, J. 



E. Benedict. Lateral and dorsal views of (j'' abdominal appendages. 

 10 and 11. Enallagrna aspersum Hagen. Conneaut Lake, Pa., August 18, 1899, 



D. A. Atkinson. Lateral and dorsal views of cJ^ abdominal appendages. 

 12 and 13. Eindlagma calverti Morse. Sheep Creek, Wyoming, August 6, 1899, 



E. B. Williamson. Lateral and dorsal views of (^' abdominal append- 



14 and 15. Enallagrna cyalhigerum Charpentier. Sheep Creek, Wyoming, August 

 6, 1S99, E. B. Williamson. Lateral and dorsal views of (^ abdominal 

 appendages. 



16. Gomphus viridifrons Hine. Ohio Pyle, Pa., June 25, 1900, E. B. William- 



son. Lateral view of (^ abdominal appendages. 



17. Gomphus viridifrons Hine. Ohio Pyle, Pa., June, 1900, E. B. Williamson. 



Vulvar lamina. 



18. Gomphus brevis Selys. Ohio Pyle, Pa., June 24, 1900, E. B. Williamson. 



Lateral view of (J' abdominal appendages. 



19. Gomphus brevis Selys. Ohio Pyle, Pa., June 28, 1900, E. B. Williamson. 



Vulvar lamina. 



