446 NEW YORK STATE MUSEUM 



apices appearing at the sides of tbe superiors; female generally without 

 thornlike Tertical spines. 



fl) Imago A single cell between veins Ai and A2 at their origin ; seg- 

 ments 8 and 9 of abdomen of about equal length, 7-9 greatly dilated, in 

 width almost equaling the thorax; vulvar lamina of the female about half 

 as long as the ninth abdominal segment. Nymph with a broad, obtusely 

 pointed abdomen; lateral spines on the ninth abdominal segment twice 

 as long as the 10th segment, the latter segment thus appearing incased 

 in the ninth ; median impressed line on abdomen distinct, and no dorsal 

 hooks except the merest rudiments on segments 8 and 9. 



&) Face of imago lineate with black. Length of full grown nym^ph 



29mm G. adelphus 



&&) Face of imago entirely yellow. Length of full grown nymph 



33 mm G. fr at emus 



aa) Imago Normally two cells between veins Ai and A2 at their origin ; 

 ninth abdominal segment a little longer than eighth; segments 7-9 

 less dilated ; vulvar lamina of female one third to one 10th as long as 

 the ninth segment. Nymph with lanceolate, pointed abdomen ; the lateral 

 spines on the ninth segment generally shorter than the 10th segment and 

 not inclosing it; dorsal hooks represented by rudiments of some of the 

 segments before the eighth; impressed middorsal line visible only toward 

 the bases of the middle segments. 



b) Imago Length 45 mm ; legs all black ; nymph unknown 



G. quadricolor 

 hi) Imago Length over 50 mm ; fore femora yellow or green below ; 

 nympli with very low, obtuse, inconspicuous rudiments of dorsal hooks. 

 c) Imago Tibiae black externally ; inferior abdominal appendage 

 male with an inferior tooth ; vulvar lamina of the female about one 

 third the length of the ninth abdominal segment. Nymph with about 

 eight to 10 teeth on the inner margin of the lateral lobe of the labium 



G. descriptus 

 cc) Imago. Tibiae yellow externally ; superior abdominal append- 

 age of the male with an obtuse inferior lobe; vulvar lamina of the 

 female about one 10th as long as the ninth abdominal segment. 

 Nymph with about six to eight teeth on the inner margin of the 



lateral lobe of the labium , G. sordidus 



b&&) Imago Length about 48 mm ; tibiae yellow externally ; yellow 

 on the dorsum of abdominal segments 9 and 10. Nymph with pointed 

 rudimentary dorsal hooks on segments 6-9 G, exilis 



Subgenus gomphurus 



Imago, A single cell between veins Ai and A2 at their origin, hav- 

 ing a thickened margin, forming an anal loop; abdominal segments 7^9 

 greatly dilated, as wide as or wider than the thorax : eighth segment cut 

 squarely on apex; posterior hamule of male perpendicular; hind femora 

 similar in the two sexes. 



