Catalogue of the Odonata of Ohio. 



207 



Length of abdomen % 9 24 mm.; hind wing, % 17 mm.; 

 9 19 mm. 



Male. — Labrum, anteelipeus, gense and frons orange; the 

 labrum has three black points at base ; vertex, occiput, upper 

 part of eyes and antennae black ; cuneiform post-oculars con- 

 nected and greenish-blue ; head below pale yellow. The 

 prothorax is black above, with orange, as follows : Anterior 

 lobe with a broad transverse line, middle lobe with a gemi- 

 nate spot in the center and a larger spatulate one each side, 

 the posterior lobe with three small spots, below and on sides 

 pale orange. The " thorax" bronze-black with dorsal carina 

 (sometimes only anteriorly) and humeral stripe bright orange ; 

 the legs yellow, with a black line on the outside of the fem- 

 ora and tibiae (these lines are lightest on the hind pair). The 

 wings are hyaline, pterostigma small, reddish-brown. The 

 abdomen is slender, dorsum of 1-8 and 10 bronze-black, 9 

 blue, sides and below yellowish-green anteriorly and bluish 

 posteriorly ; the tenth segment is prolonged and bifid to 

 about the same extent as in Enallagma exsulans; the superior 

 anal appendages are one-fourth shorter than 10, black, bifid, 

 the upper branches divaricate, curved inward and bearing a 

 minute hook at the inner distal angle; the inferior branches 

 are stouter, shorter, obtuse, converging with a slight curve 

 outward ; the inferior appendages are yellow, tips blackish, 

 they turn outward and upward so that the tips rest in the 

 forks of the superiors. 



Female. — Head as in the male, except that the colors are 

 less vivid ; prothorax and thorax are similar, except the mid- 

 dorsal carina is more strongly marked with yellow, pterostigma 

 lighter; abdominal dorsum is wholly bronze-black, although 

 somewhat narrowed on 1, 2, 9, and 10, below greenish-yellow, 

 ventral spine on 8 prominent, valves yellow. 



This form was first taken and studied at Columbus, by Dr. 

 Paul Fischer, for whom I propose the name. 



The redresse tenth abdominal segment and the male anal 

 appendages ally it to Ischnura, but the pterostigma is pre- 

 cisely the same on all wings, and the females are not dimorphic, 

 so, while it agrees with /. carvula somewhat, I prefer to re- 

 gard it as Enallagma, i. e., differing from the typical forms 

 in the same way that Exsulans does. As regards its place 



