4 University of Michigan 



9. Anal area in the hind wings, distal to the postanal cells, 

 two cells wide: Archaeogomphus, Agriogomphus, 

 Cyanogomphus, Ischnogomphus, Microgomphus. 

 9a. Anal area in the hind wings, distal to the postanal cells, 

 three cells wide: Epigomphus, Cyanogomphus, Lepto- 

 gomphiis. 

 9b. Anal area in the hind wings, distal to the postanal cells, 



four or more cells wide: Macrogoniphus. 

 10. Anal triangle present in the male : Cyanogomphus, Lepto- 



gomphus, Macrogoniphus. 

 loa. Anal triangle not present in the male: Archaeogomphus, 



Epigomphus, Ischnogomphus, Microgomphus. 

 lob. Male not known: Agriogomphus. 



An Artificial Key to the Genera of the Group 



a. Basal antenodal of second series not present. 



b. One row of postrigonal cells in the front wings 



Archaeogomphus. 



bb. Two rows of postrigonal cells in the front wings. 



c. Anal area in the front wings one cell wide, in the 



hind wings two cells wide Microgomphus. 



cc. Anal area in the front wings two or more cells wide, 

 in the hind wings three cells wide . . Leptogomphus. 

 aa. Basal antenodal of second series present. 



b. Anal area in the front wings one cell wide. 



c. One row of postrigonal cells in both front and hind 



wings Agriogomphus. 



cc. Two rows of postrigonal cells in both front and 



hind wings Ischnogomphus. 



bb. Anal area in the front wings two or more cells wide, 

 c. Distal thickened antenodal the hhh . Cyanogomphus. 

 cc. Distal thickened antenodal the sixth or more distal. 



