74 DRAGONFLIES OF NORTH AMERICA 
usual middorsal pale stripe on the abdomen is invaded at the sides by brown 
and bilobed on segments 1 to 3 and to a less extent on 4 to 8 where becoming 
abbreviated, reduced on 9 to a small round spot, and outspread again to cover 
10. Segments 7 to 9 are broadly yellow on the moderately dilated side margins. 
16. Ophiogomphus severus Hagen 
Hag. ’74, p. 591: Mtk. Cat. p. 85: Kndy. ’15, p. 341 and ’17, p. 531 (figs.). 
Whitehouse 717, p. 99. 
Length 53 mm. Expanse 68 mm. Colo., Wyo., N. M. 
This is a large greenish gray desert species, with scanty development of color 
pattern. Face and hornless occiput yellow, the latter with touches of black on its 
outermost angles. Thoracic stripes 1, 2, 4, and 5, obsolete, and 3 represented 
m 
severus 

by a very narrow and obscure pale brownish line. Legs blackish, yellow before 
the knee, on the outer face of tibiae and tarsal segments. Wings hyaline, costa 
yellow, stigma tawny. The usual pale color of the dorsum of the abdomen 
overspreads the sides of the basal segments but is delimited in the rear by black- 
ish V-marks on segments 2 to 9; 10 obscure. Appendages yellow. 
Whitehouse (’17, p. 99) says that this species frequents sandy roads 
near the river and rests on the soil frequently. Kennedy (’15, p. 341) 
observed that 
On Satus Creek south of Alfalfa (Washington) the emergence commenced 
the second week in June and lasted until the first week in July. It occurred from 
9 o’clock in the morning until 4 o’clock in the afternoon, the nymph seldom 
crawling more than six inches from the water. Oviposition was most common on 
about August 1 and the last specimens were seen August 24. Oviposition occurred 
