Occasional Papers of the Museum of Zoology 7 



in the front wing and 4 to nearly 5 in the hind wing. Ante- 

 nodals front wing 12, hind wing 8 or 9 ; postnodals front wing 

 7, hind wing 7 or 8, basal antenodal of second series present ; 

 the distal thickened antenodal the fifth. Subtriangle in hind 

 wing free, all other triangles and siibtriangles once crossed. 

 Anal fields as in the male. 



Legs as in the male, slightly paler in color. 



Material Studied : Gualan, Department Zacapa, Guatemala, 

 June 16, 1909, two males and one female, one male and the 

 female the type and allotype respectively, in coll. E. B. W. 

 Named for Dr. F. Ris, whose many acts of personal kindness, 

 as well as his valuable contributions to Odonatology, are grate- 

 fully acknowledged by the author. A male and female of this 

 species, same locality and date, not studied in the preparation 

 of this paper, are in Dr. Calvert's collection. These specimens 

 and specimens of P. pygmaens from Colombia, sent to Dr. 

 Calvert by me, have been carefully studied by Dr. Calvert and 

 compared with de Sely's original description of pygmaeus and 

 with specimens of that species from Costa Rica in his collec- 

 tion. His notes on all this material have been placed at my 

 disposal. His conclusion is that the Gualan species, here de- 

 scribed as risi, is new and distinct. Drawings of the abdom- 

 inal appendages of risi were sent to Dr. Ris who also pro- 

 nounced the species new. 



Remarks : Progomphus risi, next to P. pygmaeus and pcr- 

 pusillus, is the smallest species of the genus. From pygmaens 

 it is separated in both sexes by the following venational dif- 

 ferences : anal field in front wing one cell wide throughout in 

 pygmaeus, two cells wide for short distances both proximal and 

 distal to the level of the triangle in-risi; three cells in the prox- 

 i'mal row of postanal cells in the hind wing in pygmaeus, four 

 cells in risi. In both sexes of pygmaeus the legs, especially the 



