220 PHILIP p. CALVERT. 



Subfamily 6. Cordulinx. — Hind margin of eyes produced as a small tubercle. 

 Usually a small bundle of fine hairs ou the distal anterior surface of the 

 first femora. Males with auricles on 2, anal margin of hind wings ex- 

 cavated, distal end of first tibife with an inferior carina. 



Subfamily 7. LibeUulinai. — Hind margin of eyes not produced as a small tu- 

 bercle, or with a mere trace of such. Males without auricles on 2, anal 

 margin of hind wings not excavated. 



Characters of the Genera (imagos only). 



Subfamily 1. CALOPTERYGIN^. 



Legion Calopteryx Selys. — Sectors of the arculus arising from below its middle, 

 antecubitals of first and second series nearly equal in number, quadri- 

 lateral as long as the basilar space, pterostigma absent or of one to several 

 cells. Epistoma not projecting as much as the length of the eyes. 



Basilar space free, arculus broken, an inferior branch to the lower sector of 

 the triangler quadrilateral straight;" % superior appendages forcipated,-" 

 no pterostigma ; 9 pterostigma absent or present 1. Calo|>teryx. 



Basilar space cross-veined, arculus not broken, no inferior branch to the lower 

 sector of the triangle ^ % wings with a basal red spot, cells of postcostal 

 space ou front wings irregular.. 2. Hetseriiia. 



Subfamily 2. AGEIONIN^. 



/. Legion Lestes Selys. — Median and subuodal sectors parting from the principal 

 sector much nearer the arculus than the nodus; % superior appendages 

 forcipated. 

 Nodal sector parting from the principal 3-5 cells after the nodus ; supplemen- 

 tary sectors between the subnodal and the median, and the median and 

 the short and other sectors; hind margin of the prothorax rounded, 



entire; pterostigma 3-4 times as long as broad 3. Lestes. 



II. Legion Agrion Selys. — Median and subnodal sectors parting from the principal 

 near the nodus; quadrilateral trapezoidal, upper side shorter than the 

 lower, lower external angle acute ; no supplementary sectors except the 

 ultra-nodal ; lower sector of the triangle extending to the hind margin 

 of the wing; pterostigma of but one cell. 

 Hairs of thetibife about twice as long as the intervals between them ; a single 

 row of postcostal cells; arculus complete, lying in the prolongation of 

 the second antecubital ; tarsal nails toothed, tooth shorter than the nail 



proper 4. Argia. 



Hairs of the tibire never twice as long as, but generally shorter than, the in- 

 tervals between them; otherwise as in Argia. (In all the following 

 genera the postcostal vein separates from the hind margin in front of 

 the basal postcostal cross-vein.) 

 A. 9 with no apical ventral spine on 8. Pterostigma similar ou front and 

 hind wings. 

 No pale postocular spots ; color brown and blue or yellow:< l . .,^ /^ n-i., » -ji^, 



5. Ery^thromma. 



Pale postocular spots or line present; color metallic, similar in % and 9; 



abdomen extremely slender 6. Kehaleniiia. 



