1 8 University of Michigan 



PLATE I 



Figs. 1-3, diagrams of thoracic color patterns. Fig. i, Progomphus 

 risi, male, Gualan, Guatemala; fig. 2, Progomphus pygmaeiis, male, 

 Bolivar, Colombia; fig. 3, Progomphus sp., female. La Tigrera, Colom- 

 bia, December 20, 1916. 



Fig. 4, accessory genitalia of the second abdominal segment of Pro- 

 gomphus pygmacns, male, Bolivar, Colombia, December 24, 1916. 



