102 DRAGONFLIES OF OHIO. 



PLATHEMIS, Hagen. 



The single Ohio species of this genus has the ap- 

 pearance of a Libellula, but the pair of hooks on the 

 under side of the first abdominal segment of the male 

 characterizes that sex. The female is much like L. 

 pulchella. but its much smaller size will separate it from 

 that species. 



Plathemis trimaculata, De Geer. 



Length : of abdomen cT 28, 9 24 ; hind wing o* 32, 9 

 35. 



Male, colors brown and yellowish. Front brown, 

 labrum and labium yellowish, rear of eyes brown with 

 two bright yellow spots on each side. Thorax each 

 side with two oblique, white stripes each terminating 

 below with a yellow spot. A row of oblique yellowish 

 spots on each side of the abdomen from 2-9. Wings, 

 at base with a brown patch which in width extends 

 from above the subcosta to the postcosta and in length 

 about one fourth the extent of the wing, at middle with 

 a brown patch covering the whole width, and in length 

 reaching from before the nodus to about the middle of 

 the pterostigma, apex from thence hyaline. 



The female has the basal patch brown as in the 

 male, a large nodal patch not reaching the posterior 

 margin, and the apex of the wing from the middle of 

 the pterostigma, brown. 



The species is common everywhere, and may be 

 seen resting on logs and fences along the edges of 

 woods, as well as flying over stagnant ponds and run- 

 ning streams. 



CELITHEMIS, Hagen. 



The members of this genus are all graceful and 

 active species. The wings are ample and variously 

 marked, even in the same species. As they fly along 

 the margins of ponds and lakes they are very attractive 



