290 ENTOMOLOGICAL NEWS. [July, 'l/ 



the penis could not be used as a specific character because of 

 the lack of sufficient specific difi^erences. 



The present paper deals with a third condition, one that 

 can be said to be intermediate between the preceding. It 

 deals with a group in which the penis is a good generic as 

 well as a good specific differential. As in the second paper, 

 this group was chosen because of its immediate availability 

 through Mr. Williamson's review of the genus Neoneura and 

 his recent work on related genera.* It is offered as a sup- 

 plement to his delimitation of genera and species in this 

 Legion. 



As in venation, the penis in the Legion Protoneura is re- 

 duced to a comparatively simple form, though it is not as re- 

 duced as in the Legion Lestes. Notwithstanding this reduc- 

 tion, ample variety of form yet occurs for the distinction of 

 genera and species. By referring to the description and text- 

 figure in my first article {loc. cit.) it will be seen that the penis 

 in this group approaches nearly to this simple, generalized 

 form. In most genera of the Legion Protoneura the terminal 

 fold is lacking, though even this occurs in the genera Palaem- 

 neina and Platysticta, while it appears in a less degree in Dis- 

 paroneiira, Caconciira and Isosticta. 



In the first series of figures accompanying this article are 

 shown the penes (as far as I have been able to obtain them) 

 of the type species in the greater number of the genera now 

 accredited to this Legion.t With each, where possible, is 

 shown the penis of a second species in the same genus to 

 show at a glance those characters common to the two (generic 

 characters) and those characters peculiar to the individual 

 (specific characters). In the second series of figures are 

 shown the penes of the species of the genus Neoneura. 



*Notes on Neotropical Dragonflies or Odonata, Proc. U. S. Nat. 

 Mus., Vol. 48. May 12, 1915, pp. 616-636. A new Dragonfly genus of 

 the Legion Protoneura. Ent. News, Vol. xxvii, pp. 30-33, Jan., 1916. 

 The genus Neoneura. Trans. Amer. Ent. Soc. xliii, pp. 211-246, pis. 

 ix-xix, 1917. 



fl am indebted to Mr. Philip Alunz. who is working out the vena- 

 tional problems in the Zygoptera, for his list of these genera. 



