No. 39] ODONATA OF CONNECTICUT! GOMPHIDAE MS 



20. Metepisterna infuscated; dorsum of abdominal segment 9 with a 



broad yellow dorsal stripe graslinellus 



Metepisterna not infuscated; dorsum of abdominal segment 9 with- 

 out a broad yellow dorsal stripe 21 



21. Fronto-clypeal suture usually with a black stripe; labrum with 



black ; yellow spots of abdominal segment 8 less than half the 

 length of that segment ; anal appendages as in Fig. 23, Nos. 



14, 15 crassus 



Fronto-clypeal suture without a black stripe ; no black on the 

 labrum or very little ; yellow spot on abdominal segment 8 more 

 than half the length of that segment 22 



22. Pale stripes of the mesepisterna about equal in width vastus 



Pale stripes of the mesepisterna very unequal in width 23 



23. Hamule of the second abdominal segment with a prominent angle 



at middle when viewed from the side (Fig. 21, No. 5) fraternus 



Hamule of the second abdominal segment without a prominent 

 angle at middle when viewed from the side 24 



24. Superior anal appendages as in Fig. 23, Nos, 12, 17 (externus) 



Superior anal appendages as in Fig. 21, No. 9 ventricosus 



Fig. 19. Tip of abdomen of Gomphus ventricosus from above showing 

 expanded condition and color pattern. 



Females 



1. Occiput rounded and without a distinct superior transverse ridge.. 2 

 Occiput with a distinct superior transverse ridge S 



2. Compound eyes i mm. apart or less at their dorso-mesal angles . . 3 

 Compound eyes more than i mm. apart at their dorso-mesal angles 4 



3. Superior anal appendages black ; vulvar lamina more than half as 



long as the ninth sternum (Fig. 20, No. 2) ...(Lanthus) parvulus 

 Superior anal appendages pale ; vulvar lamina less than half as 

 long as the ninth sternum (Fig. 20, No. 3) . . (Lanthus) albistylus 



4. Vulvar lamina more than half as long as the ninth sternum, the 



sides concave and the plates slender distad (Fig. 20, No. 4) ; a 



black stripe on the fronto-clypeal suture brevis 



Vulvar lamina less than half as long as the ninth sternum, the 

 sides convex and not more slender distad (Fig. 20, No. i) ; no 

 black stripe on the fronto-clypeal suture abbreviatus 



5. Abdomen 45 mm. or more in length spiniceps'* 



Abdomen less than 45 mm. in length 6 



6. Ventral margins of terga 8 and 9 nearly straight, when viewed 



from the side, not extending further ventrad than 3 to 6 and 

 usually parallel with the margins of those segments 14 



^Vulvar lamina longer than broad, the tips rounded lineatifrons 



Vulvar lamina broader than long spiniceps 



Plagiatus also falls here but is distinguished by the reddish-brown color of the abdo- 

 men, the caudal segments being nearly uniform brown. Externus is a western species 

 not found in New England. 



