46 DRAGONFLIES OF OHIO. 



with black on the back of 1-8 and 10, basal yellow- 

 rings on 1—7. 



The male abdominal appendages yellow, tips black, 

 longer than 10, compressed; from above sides parallel, 

 end round internal tooth ; from side upper line straight 

 lower divergent, shortest, hence the end is obliquely 

 truncated with tooth at lower angle ; inferiors slender 

 curved inwards, much shorter than the superiors. 



The female has the same general colors, usually a 

 little paler; the post-clypeus is all black, the legs are 

 yellow but have narrow black stripes; the dorsum of 

 rings 1—9 are black, 10 yellow, sometimes the apex of 

 9. The slender appendages are all yellow, valves 

 and processes the same. 



Signatum is very numerous about canals, slow 

 rivers and ponds. 



Enallagma pollutum, Hagen. 



Length of abdpmen d" 29, 9 29 ; of hind wing d 19, 

 9 20. 



Male bright yellow, greenish yellow, pale blue and 

 black. The occipital spots are long, narrow, connected 

 greenish-yellow; the frons including the autennas and 

 rings or half rings about the ocelli, face and lips, except 

 two transverse black lines in the postclypeus and three 

 points at base of labrum yellow ; prothorax yellow- 

 below and on sides, top black with large anterior spot, 

 one on each side, another double one in the middle and 

 the posterior edge yellow ; the thorax is yellow with 

 black mid-dorsal and a narrow humeral with irregular 

 edges, the humeral is sometimes a mere brown stain ; 

 the legs are yellow with spines and rings on tarsi and 

 claws dark brown. Abdomen attenuate wider post- 

 eriorly, dorsum black as follows: 1, except apical 

 yellow ring, all of 2-8 except basal bluish ring on 3-7 

 (9 is blue), 10 with a cross of black, the rest blue. 



