202 
10 
11 
DRAGONFLIES OF NORTH AMERICA 
Bisector of anal loop nearly straight; wings often highly colored.3. 
Bisector of anal loop strongly angulated at level of heel........ 4, 
Fore wing triangle with front side as long as inner side......... 
he et Eee GS SDI Pee Perithemis, p. 205 
Fore wing triangle with front side half as long as inner side..... 
Si coxtapeag Re Ree Ete cee her eg PTR, the eae eae Celithemis, p. 207 
Fore wing triangle with front side one third as long as inner side 
SE Py SN oe AN |G CE ERM AT Pseudoleon, p. 213 
ns 
. 
15° y 

Celithemis Sympetrum Dythemis 
Fia. 38. Diagram illustrating angulation of bisector of anal loop. 
Ends ofstiema parallel .).06c5 oh Oe Gagan ae 5. 
Ends of stigma convergent backward, front side much longer; Az 
straight at base with large cells behindit.................. 18. 
Bisector of anal loop deflected beyond ankle moderately (30-50) . 6. 
Bisector of anal loop deflected beyond ankle strongly (50-60); 
spines of Jers fattened :.\¢v ties bade eda se eee 16. 
Hind wing Cw, rising from hind angle of triangle.............. a 
Hind wing Cu, rising from outer side of triangle............ 14. 
Base‘of As distal: towAe oases eee Erythrodiplax, p. 214 
Base of Ae opposite Aes ost. oink mata eet eee Oe ee 8. 
Vein M; strongly undulate; stigma long, bordered behind by 3 to 6 
cells: b.veG RA BaNR) . cee ARR Re Ras ee 9. 
Vein M; smoothly curved; stigma short, bordered behind by 1 or 2 
2) 1 ante tlie aah gc Lie tons hr Md A UMM RROD Why over AS) 12. 
Veins M,_3 and My, separate almost from the arculus.......... 10. 
Veins M,_3; and M, stalked beyond the arculus. .Orthemis, p. 216 
Vein M,, rising under proximal fourth of stigma. .Ladona, p. 217 
Vein M,, rising under middle third or beyond.............. 1 
Wings alike in the two sexes; male with no ventral hooks on seg- 
THONG Goren oe Peis a Ree LEE On ee eer Libellula, p. 119 
Wings unlike in the two sexes; male with a pair of ventral hooks 
on 1. De ee eee Plathemis, p. 228 
