176 Annals of the Carnegie Museum. 



black spots on 9. Abdomen c? 20.5-23, 9 20.5-22 ; hind wing c? 



Habitat : — Brazil, Sao Paulo, September 14, 1900, by A. Hempel, 

 3 pairs (the 9 9 form b of Ris), no. 303 ; and Rio Grande do Sul, 

 by H. v. Ihering, 2 d\ 2 $ (form a of Ris), no. 330. Academy of 

 Natural Sciences of Philadelphia. 



Argentina, Santa Helena, December 21, by H. H. Smith, 1 9 

 (form a of Ris). Carnegie Museum, Pittsburgh. 



Subspecies ? rusticum : Brazil, Bahia, 1 $ and parts of 1 other ? 

 and of 1 9. Museum of Comparative Zoology, Cambridge, Mass. 



Judging from the scanty material before me the females of cheliferum 

 (and rust/cum) differ from those of ambiguum by the wider head, 

 3.1-3.2 mm., as compared with 2.8 mm., and the lower, less deeply 

 bilobed, hind prothoracic margin. 



85. Acanthagrion ambiguum. 



(Plate V, fig. 97.) 

 Acanthagrion ambiguum , Ris, Hamburg. Magal. Sammelr., Odon., p. 13, fig. 8 

 (apps. $ ). 1904. 25S3 



In the present material : the costal edge of the pterostigma varies 

 from longer than, equal to, to shorter than the proximal or distal 

 edges ; M 2 on the hind wings arises nearest the fourth postnodal in 

 one male and the female, nearest the third on the right side and mid- 

 way between third and fourth on the left side of the other male. 

 The female seems to be form b of Ris, or perhaps is intermediate be- 

 tween b and c ; its colors are somewhat faded, its prothorax is reddish, 

 with a transverse black line between the middle and hind lobes ; hind 

 margin a little higher than in the d\ rather deeply bilobed. 



Abdomen c? 19, 9 20 ; hind wing cT 12, 9 14 mm. 



Front wings with 8-9 postnodals, hind wings 6-7. 



Habitat: — Paraguay, Villeta, by H. H. Smith, 2^1 9. Car- 

 negie Museum, Pittsburgh. 



86. Skiallagma simulacrum, sp. nov. 



(Plate V, figs. 95, 96.) 

 d\ Vertex obscure olive, areas corresponding to the pale postocular 

 spots of allied genera blackish, or dark metallic-green ; a reddish line 

 between each lateral ocellus and the base of the antenna of the same 

 side ; face up to, and including, the second antennal joint pale greenish- 

 blue ; rear of the head pale blue ; labium cream-colored. 



