CORDULEGASTER 151 
rapidly coming darkness of the tropical night combine to form a scene to fire 
the imagination. They come from everywhere, the air is filled with them, some 
fly erratically, others patrol regular beats, apparent spots of greater density lure 
the collector from one point to another. As suddenly as they appeared, only a 
few are seen, and then they are gone, and the disappointed collector with 
possibly only two or three specimens in his bottle, realizes that the twenty or 
thirty minute flight is at its end, and that he will not see nervosa again for 
twenty-four hours. 
Dr. W. T. M. Forbes reports that the night-jars take their toll of 
Gynacanthas during this same half hour of evening flight. 
The brownish coloration of this species is of a type that seems to 
go with crepuscular habits of flight. Dusk-flying and shade-dwelling 
dragonflies run to somber browns. 
112. Gynacantha bifida Rambur 
Ramb. ’42, p. 213: Mtk. Cat. p. 107. 
Length 74 mm. Expanse 104 mm, Fla. 
Face yellow. Top of frons with an ill-defined T-spot. Occiput yellow. Thorax 
brownish on a yellowish background. Feet yellowish. Wings hyaline, broad, 
with open venation; costa and stigma yellowish red; membranule whitish, very 
small; a brownish streak along the subcostal space extends beyond the nodus 
the length of the wing, and overlaps a little into the costal area before the nodus; 
anal triangle of three cells. Abdomen brown with streaks of black on the second 
segment and median streaks of yellow on the following segments. Appendages 
brown. 
