132 Mr. H. Campion on some 



Gomphoides distinguendus, sp. n. 



Aphi/lla dentata b, Ria, Hamburg. Magalbaen. Sammelreise, vii., 



Odonaten, p. 16 (1904). 

 Gomphoides dentata, Ris, Mem. Soc. Ent. Belg. xxii. p. 74, fig. 15 (J 

 anal appendages, &c.) (1913). 



A long series of this species was taken near Buenos Ayres 

 by Dr. F. Ris in December, 1890, and January, 1891, and two 

 males were given by the collector to De Selys Longchamps, 

 who considered them to be conspecific with his G. dentatus 

 from the Amazon. When dealing with this species in 1904 

 Dr. Ris referred to the uncertainty attending its identification, 

 but decided to adopt, provisionally, the name which De Selys 

 had applied to it. At the same time he published a full 

 description of both the sexes, so that future recognition might 

 be facilitated. 



I am again indebted to M. Sever in for the loan of the two 

 specimens in the De Selys Collection, as well as tor drawings 

 and photographs (PI. VI. figs. 3-5). The study of this material 

 enables one to decide that the Argentine species is quite distinct 

 from the Amazonian one, with which De Selys had confused 

 it. I propose for it the name distinguendus, and the type of the 

 new species will be the specimen of which a description and 

 some figures are now published. In the male of G. distin- 

 guendus the superior anal appendages are bent sharply inwards, 

 and bear a strong triangular tooth internally, instead of being 

 regularly forcipate and provided with an internal swelling. 

 In dorsal view the abdomen is less swollen at segment 8, and 

 the lateral margins of that segment are not at all dilated. 

 The pterostignia is more golden than in the other species and 

 more strongly braced. There is also a venational difference — 

 between the respective holotypes, at all events — for the pairs 

 of parallel veins M 2 and Rs, M 3 and M 4 , and Cuj and Cu 2 are 

 less widely separated at the margin of the wing. Again, 

 G. distinguendus is somewhat smaller than G. dentatus, and 

 the coloration of the abdomen is more variegated (in G. den- 

 tatus the dorsum of segments 3-9 seems to me to be uniformly 

 blackish, although De Selys mentions some pale markings). 

 Finally, the colour-pattern of the thorax is different in the 

 two species, for while G. dentatus has five pairs of pale stripes 

 upon the meso-metathorax, the types of G. disti?iguendus have 

 only three pairs. Humeral stripes are certainly absent, and in 

 neither of the Brussels specimens can I perceive the narrow 

 green line on the metepisternum which seems to be indicated 

 by Ris. 



