Calvert: Odonata of the Neotropical Region. 145 



pale antehumeral stripe is one-third to one-fourth as wide as the black 

 mid-dorsal, the black humeral i^ to i^ times as wide as the pale 

 antehumeral. The black markings of 8 and 9 are due to the two mid- 

 dorsal stripes, which extend from the base to two-thirds or four- fifths 

 of the length of 8 and to one-half of the length of 9, having fused each 

 with its adjacent inferior lateral black stripe for the first half to three- 

 fifths (on 8) or third (on 9) of the segment's length, while the dorsals 

 have fused with each other for almost their entire length on 8, although 

 only at the extreme base on 9. The inner, or mesial, end of each mes- 

 ostigmal lamina is produced caudad as a slight carina, parallel to the 

 median sagittal plane of the body, as far as the level of the lower (an- 

 terior) forking of the mid-dorsal thoracic carina ; this feature is not 

 found in the females referred to A. botacudo. 



cf9- Stigma of the front wings surmounting more than one cell 

 (100 per cent. cf, 66.7 per cent. 9) or one cell (33.3 percent. 9); 

 of the hind wings surmounting more than one (50 per cent, cf, 83 

 per cent. 9), one (^^ per cent. cf, 17 per cent. 9), or less than one 

 (17 per cent, cf ) cell. 



Antenodal cells on the front wings 3 (100 per cent. cf 9), on the 

 hind wings 3 (100 per cent, cf, S^ per cent. 9) or 3 -f- (17 per 

 cent. 9). 



Postnodals on the front wings 15 (50 per cent, cf, 33-3 per cent. 

 9), 16 (33.3 per cent, cf, 50 per cent. 9), 14 (17 per cent. cf) or 

 17(17 per cent. 9). All percentages based on 3 cf 3 9. 



Dimensions: abdomen cf 26-26.5, 9 23.5-25; hind wing cf 18.5, 

 9 18-19. 5 mm. 



Habitat : — Brazil, Peixe-Boi, by Miss Harriet B. Merrill, 3 cf 3 

 9- Academy of Natural Sciences of Philadelphia and coll. E. B. 

 Williamson. Two of the males and one female are accompanied by 

 the following notes made by the collector: cf "Bright blue, darker 

 than sky blue Nov. 26, 1907"; cf "Entire body blue and black 

 Nov. 26, 1907"; 9 "Bright blue like larger one Nov. 29, 1907." 



After describing the " 9 ? (Douteuse) " of Argia impura, Selys 

 (/. c. p. 397) remarks " J'ai ete porte a admettre une difference entre 

 V impnra et la tinctipennis parce que les deux femelles, qui semblent 

 notablement differentes l'une de l'autre, se rapportent parfaitement par 

 les dimensions et le nombre de nervules postcubitales aux males que j'y 

 rapporte." The color pattern of abdominal segments 4 and 5 of the 

 males as he describes them would appear to justify the separation of 



