172 Annals of the Carnegie Museum. 



Dimensions : Abdomen 26-28.5 > hind wing 18-19. 5 > width of head 

 3.4; width of one postocular spot .72; maximum height of segment 10 

 .96 ; height of segment 9 at base .84 ; width of tip of dorsal process of 

 10 about. 16; maximum width of 10 .8 mm. The last six dimensions 

 taken from one specimen only. 



9 unknown. 



Habitat : — Brazil, Cuyaba, 7 cT and parts of 1 other; Cachoeira, 

 parts of 2 ? c? numbered 26 by the collector ; all by H. H. Smith. 

 Carnegie Museum, Pittsburgh. 



The specific name is suggested by that of the nearby Charaes, Xaraes, 

 or Jaraes marshes, taken in turn from that of a former Indian tribe. 



81. Acanthagrion chacoense, sp. nov. 

 (Plate V, figs. 90, 91.) 



d\ Vertex black, this color reaching down on the frons between the 

 antennae almost to the nasus, which is also black narrowly bordered 

 with blue along its free margin, black of frons and of nasus connected 

 by a vertical black line ; the following blue : postocular spots, a dot 

 on each side of the median ocellus, a larger spot behind each antenna- 

 base, a short line between the median ocellus and each antenna, genae, 

 external surface of mandibles, labrum (except a mid-basal black point) 

 and the labium, or the last possibly cream-color in life. Rear of the 

 head partly pruinose, but apparently largely blue. 



Prothorax black ; sides inferiorly, a dorsal spot on the front lobe, a 

 pair of short median lines on the middle lobe, a mid-dorsal trace on 

 the hind lobe, blue ; hind margin of hind lobe low, convex, slightly 

 truncated, and with a minute notch medially. 



Dorsum of meso-metathorax black ; a blue antehumeral stripe, which 

 is narrowest at two-thirds' height, and at mid-height is one-third as 

 wide as the black mid-dorsal and one-half as wide as the black humeral ; 

 black mid-dorsal much contracted at its anterior (lower) end ; black 

 humeral stripe uniting at its upper end with a short black line on the 

 upper end of the obsolete first lateral suture, at its lower end its outer 

 edge bends twice similarly to the condition described for A. chararum* 

 Sides blue, a black stripe on the second lateral suture from the upper 

 end to more than half-way to the level of the metastigma below, which 

 latter is a blackish spot. Pectus pale blue, a blackish area, covered 

 with pruinose, at the hind end. 



Dorsum of abdominal segment 1 black, (in the Corumba cT a narrow 



