124 
DRAGONFLIES OF NORTH AMERICA 
Two cubito-anal cross veins; vein M, undulate; supratriangle 
without cross veins; one cross vein under stigma............ 
5 Ra Wilner Gomphaeschna, p. 125 
Three or more cubito-anal cross veins; vein M, not undulate; 
supratriangle divided by cross veins; several cross veins under 
SULT ge asc sales gn ns Sh ae eee 3. 
Basal space traversed by cross veins............ Boyeria, p. 126 
Basal space opens 5). snc iebela ue See eee Basiaeschna, p. 126 
Sectors of the arculus separating from the arculus at or below 
its.aiddle.,.ixe .adiy Jen Geode Re. Bia eh ee eee ee ae 5. 
Sectors of the arculus springing from above the middle of the 
AFCUIUS 5 (ose <id ec a Go. Re ee Anax, p. 128 
Radial sector apparently unbranched; 2 cross veins under the 
Atimmeen! 5° ey bake Ee h nary te ee aap Oplonaeschna, p. 129 
Radial sector distinctly branched; three or more cross veins under 
SEO HNG 5G) ave sco absisusdeistaay aus: + tyne eimehe eee pr 6. 
Fork of radial sector under the middle of the stigma; outer end of 
radial planate gently curved........... Coryphaeschna, p. 131 
Fork of radial sector before the stigma; outer end of planate bent 
forward abruptly i. 5 S28) 9 A AR ee eee 7. 
Radial sector symmetrically forked; one or two rows of cells be- 
tweenit snd tts planate: .:.% . a. 6 oe wate cae 8. 
Radial sector strongly deflected towards the stigma at the base 
of its fork, unsymmetric; 3 to 7 rows of cells between it and its 
planters. Pee PLT Se ae ee 9. 
Face strongly produced above, the upper margin of the frons very 
acute; veins M, and M, parallel to the level of the stigma; the 
radial planate subtends one row of cells... Nasiaeschna, p. 132 
Face vertical, not sharply angulate at upper edge of frons; veins 
M, and Mz, approximated at the stigma; the radial planate 
subtends “urs. suturs oR. cells git chen Nae i Epiaeschna, p. 133 
Two rows of cells between Cu and Cuz beyond the anal loop of 
The Dud: WING i cea a RU ae RRR oe cache ap Aeschna, p. 134 
One row of cells between Cu, and Cu, beyond the anal loop of 
the nnd wie:\se Ve eee eee eae Gynacantha, p. 149 
Nymphs 
Lateral lobes of labium armed with strong raptorial setae 
Gynacantha, p. 150 
Lateral lobes of labium lacking raptorial setae............... 2. 
