KELLICOTT. 23 



clearer, running waters; to this there is one except- 

 ion, the young of putrida live also in deep water of 

 Lake Erie, and the nymphs swarm about its shores and 

 islands. 



Our five species fall into the two groups defined by 

 the number of cells covered by the pterostigma. 



A. Pterostigma covering more than one cell ( one and a part of 



another) putrida. 



B. Pterostigma covering one cell; males as follows: 



(1). Violet and black, 8, 9 and 10 violet; inferior appendages thick, 



much longer than the superiors and slightly notched... Wo/acea. 

 (2). Bluish and black; 9 and 10 blue; inferior appendages longer 



than the superior, apex bifid, upper branch longer tibialis. 



(3). Light blue and black; 8, 9 and 10 blue; inferior appendages 



bifid, branches equal apicalis. 



(4) Deep blue and black ; 8, 9, and 10 blue; inferior appendages 



longer, strongly bifid, branches divaricate, lower longer, stout, 



sedula. 



. Argia putrida, Hagen. 



Length ; of abdomen cT 33, 9 31 ; of hind wings cT 24, 

 9 25. 



The young are clay colored to light brown, the older 

 males are darker to black obscured by pruinose especi- 

 ally on the head, thorax and segments 9 and 10. Three 

 pale antehumeral stripes, also one on the sides of thorax 

 and narrow pale basal rings on 3-7. Segments 8-10 are 

 somewhat thickened with the last excised, sides of the 

 excison thickened and produced backwards into 

 rounded tubercles. The abdominal appendages are 

 very short, black, the superiors are flattened, obliquely 

 rounded at the end with two teeth on the lower and 

 outer side, one at the lower inner apex, the other on the 

 outer middle face, there is a sulcus between them ; the 

 inferiors are much wider vertically, beveled to an ir- 

 regular tuberculate edge posteriorly and terminating 

 above in finger-like projection that lies between the 

 tubercles of the superiors. 



The young females have a similar coloration to the 

 young males. The fully adults are light blue marked 



