150 DRAGONFLIES OF NORTH AMERICA 
The nymph is similar to that of Aeschna, but is readily distinguished 
from all other Aeschnine nymphs by the possession of a row of long 
strong raptorial setae upon the upper and inner edge of the lateral lobe 
of the labium. 
KEY TO THE SPECIES 
Adults 
1. .Eixpanse less.than 90:22...) 4034.9 Scie ee trifida, p. 150 
Expanse usually more: than, 100). 4.4.5.0) Ae) eee ee 2. 
2 Superior appendage of the male with a dorsal ridge............ 
ipiigd atv aetigh As stuie citbosay cede OS Seale Bae ae tee nervosa, p. 150 
Superior appendage of the male without a dorsal ridge.......... 
YA ho ea RT GoM, Nall oa he gee ee nn bifida, p. 151 
110. Gynacantha trifida Rambur 
The Vixen 
Ramb. ’42, p. 210: Mtk. Cat. p. 108. 
Syn: needhami Mrtn. 
Length 65 mm. Expanse 84 mm. Fla. and Calif. 
A slender graceful species with greenish thorax and brown abdomen. Face 
obscure yellowish. Apex of frons above suffused with black. Vertex blackish 
and very narrow. Occiput brown. Thorax brown and green, thinly clad with 
short, pale pubescence. Front brown, with two broad, green, obscure stripes. 
Sides more green than brown with an ill-defined oblique brown stripe upon the 
middle (stripe 4) and touches of brown upon the other sutures. Legs brown 
with black tarsi. Wings hyaline with brown veins and tawny stigma. Abdomen 
brown with blackish carinae and obscure median and subapical pale rings; the 
median ones are dilated toward the middle line on segments 3-7. The swollen 
basal segments are greenish at the sides and obscurely lineate above along the 
sutures. Appendages brown. Female with 3 black downwardly directed spines 
on segment 10 beneath. 
111. Gynacantha nervosa Rambur 
Ramb. ’42, p. 213: Mtk. Cat. p. 107. 
Length 75 mm. Expanse 106 mm. Fla. and Calif. 
A fine, big, brownish species with little differentiation of color pattern. The 
face is tawny; the frons above is diffusely blackish around the margin; the minute 
occiput is yellow. The thorax is wholly brown except for a blackish spot at the 
spiracle. The abdomen is brown with narrow black lines on the sutures encircling 
the segments. Segment 10 of the female has two black, decurved spines below. 
Williamson who has observed this species in the tropics says (’23, 
p. 40) that it 
seems essentially crepuscular in its flight. Where the species occurs abundantly 
the numbers on the wing and in sight at once, the mobile active flight, and the 
