Occasional Papers of the Museum of Zoology 33 



which alone the specific name is apphcable, has the face bright 

 Hght gold. It is, however, paler than in any other species. 

 The profile in the male is like figure 63, and in the female like 

 figure 64. As might be expected the female is very similar to 

 the female of crytJirogastnim; albifrons is a slenderer, more 

 delicate insect, with the middorsal thoracic black stripe nar- 

 rower. 



17. Hctcragrion tricellulare Calvert 



Figures 34, 35, 36, 107, 150, 151 



This large species is known only from Mexico and Guate- 

 mala. I have seen only three imperfect specimens, two males 

 and a female, studied by Dr. Calvert (3) now in the U. S. 

 Museum. The profiles are like those of albifrons. The arcul- 

 us is about .5 mm. distal to the cubito-anal cross-vein, and the 

 anal vein separates from the posterior margin at the cubito- 

 anal cross-vein or distad as far as .2 mm. The following 

 material has not hitherto been recorded : Purulha, Guatemala, 

 July II, one male, collected by Wm. Schaus, in collection of 

 P. P. Calvert. "'Purulha is correct spelling, not Purula as 

 Champion spells it." — Letter from Wm. Schaus to Dr. Cal- 

 vert. 



18. Heteragrion alienum, new species 



Figures 5, 37, 38, 39, 57, 68, 88, 89, 105, 152, 153 



This is the species described by Dr. Calvert (3) and refer- 

 red to by all authors, excepting de Selys and Hagen, as 

 chrysops. I have not seen the female of the latter species, 

 but a male in the Hagen collection, the type or one of the 

 types of chrysops, shows the distinctness of the two. The 

 hind lobe of the prothorax, as figured, seems specifically dis- 

 tinct, and the tooth on the superior appendages is triangular 

 and more basal in chrysops than in alicnuui, where it is more 



