Fig. 4:16. Wings of Progomphus obscurus 

 (Needham and Westfoll, 1955). 



1 States. 1 Another species, P. borealis MacLachlan 

 L873, is widespread in the western United States and 



Mexico, having been recorded from Arizona, California, 

 Colorado, New Mexico, Oklahoma, Oregon, Texas, and 

 Jtah. It is a grayish brown and dull yellow species. 



r The naiads of Progomphus live in the sandy beds 

 )f permanent streams and lakes. They are adept 

 jurrowers, and their colors match the sand in which 

 hey burrow. P. borealis is found in the sandy shal- 

 ows of permanent desert streams and in sandy areas 

 )f intermittent streams in the Sierra Nevada foothills. 

 Vdults rest on the banks of the streams or on snags 

 irotruding from the water. 



Genus Ophiogomphus Selys, 1854 



Ophiogomphus naiads are found in the gravelly beds 

 }f mountain lakes and streams. Adults rest on the 

 ;ravelly shores when they are not in sallies of flight. 

 , Three of the five species recognized from the 

 western United States are subject to considerable 

 variation in the development of the thoracic stripes 

 'fig. 4:17). Names based on such differences in color- 

 ition are here considered to be synonyms, although 

 subspeciation may be indicated. 



Key to California Species 



Males 



Inferior appendage broad near base and narrowing 



distally 2 



Inferior appendage slender proximally and enlarging 

 distally, the dorsal margin concave (fig. 4:17.9) (British 

 Columbia to Utah and California) (= phaleratus Needham 

 1902; = occidentis californicus Kennedy 1917) 



occidentis Hagen 1882 



Superior appendages with ventral angulation near distal 

 end bearing tiny denticulations; tibiae usually with 



outer face pale 3 



Superior appendages slender, without ventral angulation 

 and with large denticulations; tibiae black (fig. 4:17a) 

 (California, Nevada) (= sequoiarum Butler 1914) . . . 



bison Selys 1873 



Posterior hamule acutely pointed (California, Oregon, 

 Nevada) (fig. 4:176,c) (= morrisoni nevadensis Kennedy 



Reports from the far West are undoubtedly misidentification or 

 records before recognition of P. borealis as a distinct species. 



115 



Smith and Pritchard: Odonota 



1917) morriai 18T9 



Posterior hamuli- spatulate distalh (western U.S. end 

 Canada) (fig. 4: 17o>) (- mo 9el) I 1878) 



• . - . Hagen l h7 i 



Female* 



1. Occipital spurs present 2 



— Occipital spurs absont 3 



2. Head with a pair of postoeoipitul >-|>ur.s 



occidentis Hagen 



— Head without postoccipital spurs bison Bi 



3. Humeral stripe usually double morrisoni Selys 



— Humeral stripe with anterior part reduced to an oval 

 spot or absent sevens rlagen 



Naiads 



1. Lateral spines on abdominal segments 6-9 (fig. 4:19a) 



2 



— Lateral spines on abdominal segments 7-9 (fig. 4:196) 



3 



2. Lateral anal appendages about nine-tenths inferiors; 

 lateral spines on abdominal segments 7 and 8 subequal 

 (fig. 4: 19a) bison Selys 



— Lateral anal appendages about seven-tenths inferiors; 

 lateral spine on abdominal segment 8 longer than spine 

 on segment 7 (fig. 4:19e) occidentis Hagen 



3. Dorsal hooks on abdominal segments 8 and 9 weak, 

 slender, flattened; tips of hooks on segments 2 and 3 

 tapered, erect (fig. 4:19c) severus Hagen 



— Dorsal hooks on abdominal segments 8 and 9 stout, 

 erect; tips of hooks on segments 2 and 3 very blunt 

 (fig. 4:196) morrisoni Selys 



Genus Octogomphus Selys, 1873 



The genus Octogomphus is based on a single species, 

 0. specularis (Hagen) 1859. It is found along the 

 Pacific Coast, from Mexico to British Columbia. 



Adults of Octogomphus specularis (figs. 4:20; 4:21) 

 are found primarily along the upper reaches of densely 

 shaded streams in the coastal mountains. The males 

 perch on low objects in sunlit openings of the stream, 

 but the females are seldom found near the water 

 except for oviposition. 



Kennedy (1917) writes regarding an ovipositing 

 female: "She came volplaning down through an opening 

 in the canopy of alders and, while going through 

 evolutions involving several figures, 8's and S's, she 

 touched the surface of the pool lightly with the tip 

 of her abdomen at intervals of two to six feet. After 

 twenty seconds of this she airily spiraled up and out 

 into the sunshine, where she alighted on a bush on 

 the hillside above the creek." 



The naiads live in the loose trash on the bottom 

 of pools and eddies. Kennedy estimated that the 

 naiads spend three years in the water, emergence 

 occurring throughout the spring and summer. 



Genus Erpetogomphus Selys, 1858 



Members of the genus Erpetogomphus are found along 

 sandy streams in the western United States, Mexico, 

 and Central America. Two species are known to occur 

 in California. 



