Triacanthagyna and Gynacantha 9 



The study of this material, sent me by Mons. Severin, tends to confirm 

 my opinion expressed under T. scptima in the text, that septiiiia is really a 

 synonym of obscuripcnnis. Incidentally, the matter I could not understand, 

 i. e. why de Selys' collection contained only a single male of this widely dis- 

 tributed and common species, is explained ; there are seven specimens under 

 the labels trifida and satyrus. 



The study of this material also causes me to think I have included two 

 species under T. ditzleri, but at this time adequate characters for separating 

 the two are not discernible. The small specimens from Central America and 

 northern South America will probably be found to be specifically distinct 

 from the similar but larger specimens from southern Brazil. One of these 

 males is referred to in the text under T. ditzleri. Other specimens are 

 present in de Selys' collection under the label trifida. I have designated as 

 the type of ditzleri a male of the smaller northern and better known form. 

 A solution of the problem of the status of the two forms awaits adequate 

 material from southern Brazil. 



An examination of the following report on these thirty-eight specimens 

 will impress the student, I think, with at least two things. It shows again, 

 Avhat should now be well known, that differentiation among species in at 

 least certain aeshnine genera has progressed along such lines that specific 

 characters are not conspicuous or obvious to the student, however effective 

 they may be in nature. Following from this, the greatest care and discrim- 

 ination in the determination of species is necessary. Incidentally it may be 

 remarked, the description of new species in such groups, based on a single 

 female or on any other number of specimens which the particular case 

 renders inadequate, is not science but is an affliction. 



Thirty-tzvo specimens in de Selys' Collection labelled 

 Triacanthagyna trifida 



9 



Unless otherwise mentioned, in addition to labels indicated, each speci- 

 men bears the following label : Collection Selys. Triacanthagyna trifida Rb. 

 Revision Martin, 1909. Triacanthagyna trifida Rb. 



1. male | Honduras | Gynacantha trifida? R. male (in de Selys' hand) | C'est 

 espece different Forster (and on the reverse) il n'est pas trifida (all in Forster's (?) 

 hand)|. The specimen is T. septima. 



2. male.|Ci. 2.|7|. The specimen is T. septuna. 



3. female. I Mexique Salle|28|. The specimen is T. septima. 



4. female. I female i5i|Boctes (?)|6I. The specimen is T. septima. 



5. female.] 151 female |i4|i6|. The specimen is T. septima. 



6. female. |Para. Schulz (?) (in de Selys hand).|io|. The specimen is f. septima. 



7. male.|Copa Cabana|ii.3|32|. By its hamules it is T. ditcleri. In the anal loop 

 three cells in the anterior row in both hind wings. This is the larger Brazilian form 

 provisionally referred to ditzleri in this paper. 



8. female. I Botafogo|i4|. This is probably the female of the larger Brazilian form 

 referred to T. ditzleri. In the anal loop there are two cells in the anterior row in 

 both hind wings. 



g. female.|Botafogo|2i|. Same remarks as under number 8. 



