Calvert : Odonata of the Neotropical Region. 141 



black humeral stripe may affect the upper half thereof; superior black 

 stripe of abdominal segment 2 not narrowed at its hind end, except 

 when the right and left stripes meet on the dorsal and separate the 

 dorsal violet into a larger anterior and a smaller posterior spot, side or 

 this segment chiefly yellowish, with only a short oblique blackish streak 

 at the hind end ; mid-dorsal blue on 5 and 6, very narrow, but reaching 

 to four-fifths of 5, three-fifths of 6 ; inferior line on the sides of 3-7 

 in younger individuals very faint on 3-6, black, and not fused on 7, in 

 older females black, and fused with the superior black at the hind end 

 only of 3-5 or 6, or at both fronts and hind ends of 6 and 7, or for the 

 whole length on 7 ; 8 and 9, in addition to the inferior black stripe on 

 each side as in the male, have a pair of dorsal black stripes, pointed 

 posteriorly, reaching from the anterior end of each segment to three- 

 fifths of 8 and to one-half of 9, barely confluent with each other at the 

 extreme base of 8 only, not confluent with the inferior stripes on 8 

 and barely so on 9 ; 10 may have an inferior lateral black stripe as in 

 the male, or only a small lateral spot, or no markings. 



cT9. Stigma of the front wings surmounting more than one (75 per 

 cent. d\ 80 per cent. 9), one (15 per cent. d\ 20 per cent. 9), or 

 less than one (10 per cent. cT) cell ; of the hind wings surmounting more 

 than one (90 per cent, c?, 80 per cent. 9), or one (10 percent. d\ 

 20 per cent. 9 ) cell. 



Antenodal cells on the front wings 3 (90 per cent. d\ 100 per cent. 9 ) 

 or 3 -f (10 per cent. (J) ; on the hind wings 3 (95 per cent, <3\ 100 

 percent. 9) or 2 (5 percent, c?). Percentages based on 10 cJ', 10 9« 



Dimensions. Abdomen c^ 25-28, 9 22-26 ; hind wing cT 18.5— 

 20, 9 17. 5-21 mm. 



Habitat : — Brazil, Chapada, by H. H. Smith, 8 c? and parts of 9 

 others, some dated May, some numbered 165, 118, 4 9 ar >d parts of 

 9 others some numbered 165. Carnegie Museum, Pittsburgh. 



53. Argia thisma sp. nov. 



(Plate IV, figs. 75, 75a; Plate VIII, fig. 144.) 

 cf. Rear of the head black, a pale stripe along each eye-margin. 

 Pale (violet) antehumeral stripe one-half to one-third as wide as the 

 black mid -dorsal. Black humeral stripe of subuniform width, one and 

 a half to two times as wide as the pale antehumeral, forked only in its 

 extreme upper end, both the humeral and the mesepimeral branch of 

 the fork reaching to the upper margin of the sclerite. A black line or 



