Calvert : Odonata of the Neotropical Region. 173 



transverse apical blue ring), sides blue; dorsum of 2 black, sides, a 

 narrow transverse basal ring (mid-dorsally interrupted by a fine black 

 line) and a very fine transverse apical ring, blue; dorsum of 3-7 

 black, this color narrowed at four-fifths of each segment's length and 

 widened greatly in the hindmost fifth ; sides and a transverse basal ring 

 on these segments blue; 8 and 9 blue; 10 black, except ventrally, other- 

 wise as in A. chararnm. 



Superior appendages very similar to those of A. chararum, but in 

 profile view a little thicker at the base, decreasing in thickness more 

 rapidly in the proximal half. Inferiors as in A. chararum. 



Legs pale blue ; femora with a superior stripe, tibiae with an anterior 

 line, black. 



Wings uncolored, stigma rhomboidal, blackish, its costal edge 

 equal to, or slightly longer, or slightly shorter, than the proximal or 

 distal edges. Front wings with 10-12 postnodals, hind wings with 

 8-9 ; M 2 on the latter arising nearest the fourth postnodal, or between 

 the fourth and fifth. 



Dimensions : Abdomen 25-26 ; hind wing 17 ; width of head 3.32 ; 

 width of one postocularspot .52 ; maximum height of segment 10 .92 ; 

 height of segment 9 at base .76 ; width of tip of process of 10, end 

 view, about .16 ; maximum width of 10 .84 mm. 



$ unknown. 



Habitat: — Bolivia, Piedra Blanca, April, 1 <j\ 



Brazil, Corumba, May, part of 1 <$. Both specimens by H. H. 

 Smith, Carnegie Museum, Pittsburgh. 



82. Acanthagrion chirihuanum, sp. nov. 



(Plate V, figs. 93, 94.) 



c?. Upper surface of the head olive, passing gradually into greenish- 

 blue on clypeus and labrum ; each large blue postocular spot is bounded 

 anteriorly and posteriorly by an ill-defined blackish line, these lines 

 being the only black markings on the head. Rear of the head blue, 

 labium cream-colored. 



Prothorax blue, hind margin low, slightly trilobed, median lobe a 

 little more convex than the lateral lobes. 



Meso-metathorax blue ; a mid-dorsal black band narrowing from . 36 

 mm. at its upper (posterior) end to .24 mm. at its lower (anterior) 

 end. In the imperfect male this band is similarly proportioned, but nar- 

 rower. A short black mark near the upper end of the humeral suture 



