320 
6 
10 
11 
12 
13 
14 
15 
16 
Li 
DRAGONFLIES OF NORTH AMERICA 
Dorsum of segment 9 with a pair of dorsal black spots on the basal 
Bread os hess cw eek ve fa koon deg ek ih 
Dorsum of 9 without spots, these replaced by 2 dorso-lateral lines 
either joined or separated at the meson................... 8. 
Ten to eleven postnodal cross veins. Distribution: Eastern U. 8. 
west to: Texas ogs bibdate exsulans, p. 332, and weewa, p. 333 
Five to six postnodal cross veins. Distribution: Western U. S. 
ens to: LexaSe...05 (ota wrae Bene Oe) aan eee basidens, p. 339 
Segment 8 black with pale blue lateral spots... .divagans, p. 322 
Segment 8 blue with a dorsal stripe of black, fully four-fifths as 
wide as the segment in dorsal view........... pallidum, p. 334 
Segment 8 black on dorsum with a large blue subapical spot on 
CHCWIBIDE ee. sk. cco ideo da bce Bee ding eee 10. 
Abdominal segment 8 not so marked....................... iy 
Abdominal segment 7 black.................geminatum, p. 326 
Abdominal segment 7 blue, never with more than a line of black 
2 obs MBMeRR abt se cemeteas Sted aan gee aspersum, p. 339 
Abdominal segment 8 entirely blue........................ 12: 
Abdominal segment 8 with some black 
Dorsum of abdominal segment 2 entirely black................ 
EE EA, SY A cardenium, p. 341 
Dorsum of abdominal segment 2 blue with black spot.......... 
seats cyathigerum, p. 324; clausum p. 324, and boreale p. 323 
Black of abdominal segment 1 reaching from the base to the apex 
EPR TAR | O82 sfc Ne ee Oe AT civile, p. 336 
Black of abdominal segment 1 not reaching the apex of the seg- 
MHEG. LO Ns RR, a a ee 14. 
Western speciest! :4,h: Sua" ie aiis at nace] i ee eee eee 15. 
Basterm species ah iii 4 ot utrercerten Se Sere as eee eae 18. 
Hind margin of the prothorax convex throughout........... 16. 
Hind margin of the prothorax concave medially, slightly concave 
or truncate on either side. . .praevarum, p. 337, and anna p. 338 
Segment 9 black on dorsum, 8 entirely blue, or with black band on 
dorsum narrower anteriorly than posteriorly.............. We 
Segment 9 black on dorsum with an apical blue spot, 8 blue, apical 
fourth and sides inferiorly black and confluent..coecum, p. 341 
Mesostigmal plates with a diagonal ridge from the caudo-mesal to 
the cephalo-lateral angles.............. carunculatum, p. 335 
Without such a ridge on the mesostigmal plates............... 
SVs eh 2 eae ere ele RE cyathigerum, p. 324, and boreale p. 323 
