126 



EXPLANATION OF PLATE. 



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



Lateral view of (^ abdominal appendages. 



2. Herpetogomphug designatm Hagen. Portion of right wing; (, 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 rupinsulensis Walsh. Portion of right wing. Lettering same 



as for fig. 2. 



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



fig. 2. 



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



fig. 2. 

 ■6. Gomphus scudderi Selys. Portion of right wing. Lettering same as for 



fig. 2. 

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



fig. 2. 

 8 and 9. Enallagma doubledayi. Selys. Provincetown, Mass., August 4, 1899, J. 



E. Benedict. Lateral and dorsal views of (^ abdominal appendages. 

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



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

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



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

 ages. 



14 aad 15. Enallagma cyathigerum 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 rj 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 rj' abdoruinal appendages. 



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



Vulvar lamina. 



