OPHIOGOMPHUS 77 
The moderately dilated side margins of segments 7 to 9 are yellow, bordered 
with black distally and externally. Appendages brown. 
20. Ophiogomphus carolus Needham 
Ndm. ’97, p. 183: Mtk. Cat. p. 83: Howe ’18, p. 29: ’23, p. 129: Garm. ’27, p. 134. 
Length 46 mm. Expanse 56 mm. N. Y. 
A rather small greenish species, smartly striped with brown. Face and occiput 
yellow, the latter with or without horns. When horns are present they are small, 
a single pair, close together situated just in front of the hind (occipital) margin. 
Thoracic stripes of the first pair narrow, separate, parallel-sided, complete; 
together, narrower than the stripe of yellow at either side. Stripe 2 abbreviated 
at both ends and separated from 3 by a rather wide green stripe. Stripe 3 wider, 
especially near its upper end. Stripe 4 obsolete except for a dash below the 
spiracle, and stripe 5 complete. Legs brown, the femora paler. Wings hyaline, 
costa blackish, stigma cinereous. The middorsal line of pale markings on the 
abdomen is broadest and completest on 2, bilobed and narrowed on 8 to7 reduced 
to a small round spot on 8 and 9; 10 and appendages pale. The side margins of 
the moderately expanded segments 7 to 10 are yellowish within a narrow brown 
outer marginal line. Appendages pale. 
The nymphs may be collected by hundreds in Ithaca, N. Y. in April, 
and in May the banks of the stream are fairly covered with cast skins, 
but the adults are rarely seen. 
21. Ophiogomphus bison Selys 
Selys ’73, p. 496: Mtk. Cat. p. 83: Butler ’14, p. 346: Kndy. ’17, p. 540 (figs.). 
Syn: sequoiarum Butler 
Length 50 mm. Expanse 66 mm. Calif., Nev. 
Our largest species and a very handsome one; olive green stripes with brown, 
with half-ringed black and yellow abdomen. Face and occiput yellow, the latter 
with a pair of slender horns placed close together. Thoracic stripes of the first 
pair rather narrow, parallel-sided, constricted before the collar to a narrow line 
which crosses it. The upper angle is prolonged at the crest to join stripe 2, 
which is fused with stripe 3 in its upper third and then separated by a narrow 
greenish line below. These two stripes are rather broad and heavily colored. 
Stripes 4 and 5 almost obsolete, the former practically wanting, the latter a 
mere black line in the bottom of its suture. Legs brown, paler basally. Wings 
hyaline with black stigma. The middorsal pale stripe of abdomen is a well 
marked row of abbreviated spots surrounded and invaded at the sides by brown 
on the middle segments, broadened on 9 and wholly overspreading 10. The 
side margins of the somewhat dilated segments 7 to 9 are yellow surrounded 
distally with black. Appendages yellow, tipped with blackish. 
Kennedy (717, p. 541) says that 
“This species occurs on the smaller perennial streams emptying into San 
Francisco Bay and Monterey Bay, also on the smaller tributaries of the Sacra- 
mento River. On the Sacramento itself and its larger tributaries it appears to be 
