52 DRAGONFLIES OF OHIO. 



Hagenius brevistylus. Selys. 



Length : of abdomen d and 9 55-60 ; of hind wing 

 d and 9 48-52. 



The male is black and yeilow. Head yellow, black 

 as follows : occiput ( rear yellow ) , vertex, base of f rons 

 antense, lines between frons and clypeus and at base of 

 labrum. There is a stout vertical cone each side ; the 

 occiput is convex with a marginal fringe of black hairs. 

 Prothorax relatively small with a geminate spot in the 

 middle posteriorly ; the dorsum of the thorax is black 

 with yellow marks; semi collar, short mid-dorsal carina, 

 narrow curved line each side, narrow numerals; the 

 sides are yellow with two parallel black bands in the 

 middle separated by a yellow line, the latter interrupted 

 at the metathoracic stigmata ; the last thoracic is post- 

 eriorly edged with black. The legs are black, coxae 

 with yellow spots. The wings are slightly fiavescent, 

 costa yellow to the pterostigma which is long 5 mm., 

 yellowish, covering 6-8 cells. The abdomen is black 

 with a mid-dorsal yellow band on 1-8, more or less in- 

 terrupted at apex of 3-7, on 8 there is a large basal 

 trowel shaped triangle ; the sides of 1-9 are yellow ; 8 

 and 9 are slightly expanded laterally ; the yellow on 

 side of 8 occupies the entire length, on 9 it is lunate, 

 shorter than the ring. 



The abdominal appendages are shorter than 10, 

 black. The posterior border of 10 is straight, super- 

 iors wide apart, slightly curved inwards, outer angle 

 rounded, apex obtuse ; in profile the upper border is 

 curved downwards, apex prolonged in a sharp spine, 

 anterior to it near the inner border there is another 

 shorter and stouter one, and on the outer edge near the 

 base there is a downwardly and outwardly directed pro- 

 cess. The inferiors are united, broad, apex slightly 

 excavated, apex directed upwards. 



The female is very similar; 8 and 9 are consider- 

 ably expanded laterally ; appendages black, as long as 



