PLATHEMIS. 149 



PLATHEMIS Hagen. 



Eyes connected in a short space ; posterior lobe of the pro- 

 thorax small, entire; the abdomen short, broad, depressed; the 

 legs stout, short; pterostigma long, oblong; the first sector of the 

 triangle sinuated ; the triangle narrow, long ; caudal appendages 

 short ; genital organs of the male rather prominent ; the first ab- 

 dominal segment, beneath, with a large, prominent fork ; vulva 

 disclosed, the segment following it excavated in the middle, bitu- 

 berculated ; the eighth segment in the female dilated at the sides. 



1. P. trimaculata! 



Libellula trimaculata De Geer, Mem. Ill, 556, 2; pi. xxvi, fig. 23. Fab. 

 Ent. Syst. II, 374, 5. Burm.! Handb. II, 861, 78. Ramb.! Neuropt. 

 52, 28. — Libellula lydia Drury, Ins. I, 112 ; pi. xlvii, fig. 4. Say 

 Jour. Acad. Philad. VIII, 20, 5. (Male.) 



Rufescent; thorax each side with two oblique, yellowish stripes; 

 abdomen of the male pruinose, female with lateral oblique, yellow 

 spots, margined with fuscous; feet black, base of the femora rufes- 

 cent ; wings hyaline, a basal, longitudinal stripe, which is margined 

 inferiorly with lacteous on the posterior wings, and a very broad 

 band upon the middle (J^), or with the basal stripe, a spot upon 

 the middle anteriorly, and the apex ($), fuscous; pterostigma 

 fuscous ; membranule white ; twelve antecubitals ; nine postcubi- 

 tals ; four discoidal areolets. 



Length 40 millim. Alar expanse 70 millim. Pterostigma 5 

 millim. 



Hab. It is found from Maine to Florida, and from Texas to 

 Minnesota ; also in North California. A common species. 



2. P, subornata! 



Platkemis subornata Hagen ! 



Brownish-black, thorax with a stripe each side above, and the 

 sides with two very oblique yellow stripes ; feet black ; abdomen 

 with a broad, maculose stripe each side, on the dorsum and broader 

 ones on the venter, yellow (in the male it is wanting towards the 

 apex) ; wings hyaline, a basal, fenestrated streak, and two angulose 

 bands, the one nodal, the other pterostigmatical, fuscous ; ptero- 



