Calvert: Odonata of the Neotropical Region. 139 



most of frons (there is a black line on the fronto-nasal suture), their 

 distinctly wider mesostigmal lamina, and the greater extent of pale 

 color on the sides of abdominal segments 3-7, for in difficilis $ these 

 segments have a second, or inferior, lateral black stripe, as on segment 

 2, and this may be more or less fused with the superior lateral, fusion 

 being greater on the posterior segments and increasing with age. 

 This inferior lateral black stripe is absent from hasemani ?. 



51. Argia tamoyo sp. nov. 



(Plate IV, figs. 73, 735.) 

 d\ Rear of the head black, a narrow pale stripe along each eye- 

 margin. Pale (violet) antehumeral stripe at mid-height three-fifths 

 as wide as the black mid-dorsal. Black humeral stripe at mid- 

 height three-fourths as wide as the pale antehumeral, wider at both 

 ends, upper fourth forked, both branches of the fork reaching to 

 the upper margin of the sclerite, mesepimeral branch distinctly curv- 

 ing backward (caudad) to reach the vestige of the first lateral thoracic 

 suture. A narrow black stripe on the entire length of the second 

 lateral thoracic suture. Dorsum of abdominal segment 2 violet, the 

 width of the violet being about half that of the segment, bounded on 

 each side by a black stripe as long as the segment, apparently meeting 

 its fellow of the opposite side on the dorsum in the hindmost third of 

 the segment ; 3-7 black, with a narrow transverse basal pale ring which 

 on 3 is confluent with a mid-dorsal violet stripe, tapering posteriorly 

 to about half the length of the segment ; 8-10 blue, with an inferior 

 black stripe on each side as long as the segments, 8 also with a pair of 

 dorsal spots on the posterior half of the segment, each spot tapering 

 cephalad. 



Wings slightly smoky, stigma on the front and on the hind wing 

 surmounting one cell. Antenodal cells 4 on all wings. 



Abdomen 29, hind wing 21.5 mm. 



Habitat: — Brazil, Chapada, by H. H. Smith, 1 cT. Carnegie 

 Museum, Pittsburgh. 



The specific name proposed is that of a native human tribe. 



The single specimen (type) has lost all of the left hind wing and a 

 large part of the left front. 



