2 20 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



7. Lateral thoracic spots present, usually distinct; vulvar lamina 



longer than segment 9; depth of 9 greater than its length or 



nearly equal tenebrosa 



Lateral thoracic spots absent; vulvar lamina about as long as 9; 

 depth of 9 less than its length linearis 



8. Abdomen less than 35 mm. long; both lateral thoracic spots ovate, 



clear yellow; vulvar lamina about as long as appendages ....minor 

 Abdomen more than 35 mm. long; mesepimeral spot elongate; 

 vulvar lamina shorter than the appendages 9 



9. Yellow marks of thorax and base of abdomen clear and well 



defined; no yellow spots posterior to segment 3; vulvar lamina 



bluntly pointed, not tapering and little compressed elongata 



Yellow markings of thorax and base of abdomen dull and incon- 

 spicuous except in very young individuals; yellow basal lateral 

 spots on segments 5 to 7 or 8 ; vulvar lamina slender, pointed, 

 somewhat tapering and strongly compressed williamsoni 



10. Thorax with two lateral yellow spots and yellow spots on abdom- 



inal segments 5 to 7 or 8 ; vulvar lamina as long as sternimi of 



9 or longer 1 1 



Thorax with only the mesepimeral spot present, sometimes obscure ; 

 no yellow spots on abdominal segments posterior to segment 3 ; 

 vulvar lamina a little shorter than the sternum of 9 13 



11. Abdomen about as long as hind wings or slightly shorter; mes- 



epimeral spot elongate ; posterior spots subovate ; vulvar lamina 



in natural position, declined, largely black walshii 



Abdomen slightly longer than the hind wings; vulvar lamina in 

 natural position horizontal, yellowish 12 



12. Lateral thoracic spots pale yellow, ovate, fairly well defined; vul- 



var lamina about as long as sternum of 9 or a little longer, .forcipata 

 Lateral thoracic spots ochraceous, obscure or ill-defined; mes- 

 epimeral spot elongate; vulvar lamina longer than sternum of 9 



(incurvata) 



13. With 6 to 9 cells between Mi and Mia; hind wings with a brown 



spot at base, sometimes suffused over the entire area; lateral 

 lobes of post-clypeus black, mesepimeral spots usually distinct ; 



appendages scarcely longer than the vulvar lamina (franklini) 



With II to 20 cells between Mi and Mia; hind wings more or less 

 yellow at base but without a distinct spot ; lateral lobes of post- 

 clypeus brown ; mesepimeral spot obscure ; appendages nearly 

 twice as long as vulvar lamina kennedsd 



Group I. The Metallica Group 



Somatochlora elongata (Scudder) 



Proceedings of the Boston Society of Natural History, 10: 218: 1866. 



Nymph (Fig. 43). — Labium reaching base of the mesosternum; 

 palpi with 9 crenulations, the tw^o apical ones small and close 

 together, their setae as in minor; lateral setae of the palpi 6-7; 

 mental setae 11-12, the fourth and sixth from the outside longest, 

 the first 8 longer and closer together. 



Hind wing cases extending to the middle of segment 6. 



Abdomen: broadest at sixth segment; dorsal hooks on seg- 

 ments 4 to 9, that of 4 about one-third the length of the segment ; 

 that of 5 one-half the corresponding length, the remainder about 

 as long as the segments bearing them; lateral spines of 8 and 9 



