130 DRAGONFLIES OF NORTH AMERICA 
amber yellow, except at the ends; costa yellow; stigma tawny. Abdomen pale 
at base on sides of much swollen segments, and blue beyond with a very obscure 
pattern of paired pale, dorsal markings. Appendages brown. Distinguishable, 
even in flight, from all other northern dragonflies, by the big, green body. 
The nymphs are cannibals. They climb rapidly, and swim well by 
means of ejections of water from the gill chamber. They are often 
seen half hiding behind submerged stems with the head poised low, 
and the abdomen lifted in a position of great alertness. Transforma- 
tion occurs before daybreak, usually not far from the water’s surface. 
The nymphs are sometimes found in brackish water having a high de- 
gree of salinity. 
This species is discussed at length in Part I, page 7, and is illustrated 
in our frontispiece. 
86. Anax walsinghami McLachlan 
The giant green darner 
McL. ’82, p. 127: Mtk. Cat. p. 106: Ndm. ’23, p. 129: Smn. ’26, p. 24: Byers 
aT, py OG; 
Length 105 mm. Expanse 122 mm. Calif. 
This is our largest dragonfly. Face yellow. Top of frons with an elongate 
brown spot surrounded by yellow outside of which is a circle of blue. Thorax 
green. Legs black with the front femora yellowish beneath. Wings broad with 
yellow costa and a short, narrow, brown stigma. Abdomen very long, narrow, 
blue except the first segment which is red. A mid-dorsal brown line on the follow- 
ing segments widens posteriorly almost covering 7-9 dorsally, leaving on 10 
only two blue spots. Appendages brown, short, somewhat spatulate. 
18. OpLONAESCHNA Selys 
These are brownish darners with rather short thick abdomens. Vein 
R, is unbranched, veins M, and M; are strongly convergent just be- 
fore the stigma. Vein M, bends away from M; at the beginning of the 
terminal curve. The tenth abdominal segment of the male bears a 
high median tubercle. 
There is a single Sonoran species. Nymph unknown. 
87. Oplonaeschna armata Hagen 
Hag. ’91, p. 124: Mtk. Cat. p. 104. 
Length 68 mm. Expanse 100 mm. Ariz. and N. Mex. 
This is a short brownish species with blackish side stripes and black ringed 
abdomen. Face pale greenish with yellow labrum and a broad black transverse 
spot on rounded summit of frons, often forming a T spot. Very small black 
vertex is tipped with yellow. Occiput and summit of carinae yellow. Front of 
thorax brown with 2 obscure greenish blue narrow stripes more or less interrupted 
