Occasional Papers of the Museum of Zoology 63 



Dr. Sjostedt describes three new species of Heteragrion. 

 Unfortunately at this time I had returned the borrowed ma- 

 terial upon which much of my own work had been based, and 

 I am therefore unable to study this material again in the light 

 of this new literature. 



The species described by Dr. Sjostedt may be briefly 

 discussed as follows : 



Heteragrion silvarum Sjostedt. One male and two females, 

 Amazonas, Manaos. 



Dr. Sjostedt compares his species with aurantiacum, separ- 

 ating it from the latter by its smaller size (a negligible 

 difference), by the relatively longer male superior appendages, 

 each with a relatively larger inferior tooth and with a smaller 

 number of apical spines (this last character probably without 

 value), and by the excavated posterior border of segment 10, 

 which is nearly straight in aurantiacum. Unfortunately I can- 

 not now determine how valuable this last character may prove 

 in the genus. The differences noted in the color of head and 

 prothorax of the two species are probably of value in the case 

 of the prothorax only. But in a venational character, pointed 

 out by Dr. Sjostedt, silvaruni is entirely distinct from auran- 

 tiaciiin, — the cubito-anal cross-vein near the arculus in silvar- 

 um, and much more proximal in aurantiacmn. 



Dr. Sjostedt also points out differences in size and 

 color between silvarum and cinnamomeum, macilentum and 

 beschkii. Of the other species of the group not mentioned by 

 Sjostedt there are none I think to which silvarum might be 

 referred, though there is the unidentified but probably larger 

 amasonicum to reckon with. 



In my key to males of groups i and 2 silvarum will rim out 

 to aurantiacum but from Dr. Sjostedt's description and 

 figure I believe it is more closely related to ictcricum and 



