Vol. XXVlii] ENTOMOLOGICAL NEWS. 9 



Notes on the Penes of Damselflies (Odonata). 



No. 2. The Close Relations inter se of the Hawaiian Agrionines. 

 By CLARENCE HAMILTON KENNEDY, Cornell University. 



(Plates II and III.) 



In my first paper* I discussed a genus (Acanthagrion) in 

 which the various forms comprising it were so close in color 

 and structure that many had been considered but varieties un- 

 til a study of the penes showed each form to be a good species 

 structurally, for the penes of the various species were remark- 

 ably different. 



In this paper I wish to discuss a group, the Hawaiian Agri- 

 onines, in which just the opposite relation holds. In venation, 

 color, size, and in the structure of the male claspers the Ha- 

 waiian Agrionines differ radically among themselves but the 

 penes throughout are the same type. 



This opportunity came recently while in Philadelphia when 

 I had the privilege of examining the penes of nineteen species 

 and varieties of Hawaiian Agrioninae. These were a series 

 of specimens collected by Dr. R. C. L. Perkins, and given by 

 him to Dr. P. P. Calvert. In all cases the determinations are 

 those of Dr. Perkins and so probably agree with his published 

 articles. f Lack of time prevented an examination of the 

 specimens other than of the penes. As the number of speci- 

 mens was small, in some cases there being only a single male 

 or female, an attempt to study the specimens with a view to 

 possible grouping would have been inadvisable as Dr. Perkins' 

 own studies of this group show great ranges in variation in 

 many of the species. 



Ever since I first looked over the list of Hawaiian Odonata, 

 I had been skeptical that twenty-four species of damselflies, 

 the entire damselfly fauna of this isolated region, should be 

 comprised in but two genera. Later, when I first glanced at 

 the box of specimens on which this study is based, I felt cer- 

 tain that there were at least three genera and probably more. 



*Ent. News, xxvii, 325-330, July, 1916. 



t Fauna Hawaiiensis. Vol. I, p. clxxv. ; Vol. II, pp. 63-77, 

 693-696. R. C. L. Perkins. 



