NO. 2192. DRAGONFLIES, CALIFORNIA AND NEVADA— KENNEDY. 535 



series of triangular spots, one each on segments 3, 4, and 5 and which 

 widens caudad to 1.5 mm. on segment R. On each segment a broad 

 band across the apical end, occupying the apical fom*th on segments 

 3, 4, and 5, apical third on 6 and 7, and apical half on 8 and 9. 

 In some specimens the lateral bands are most widely connected dor- 

 sally on segment 6, being less widely connected on segments 7-9. 

 No connecting apical band on segment 10. Appendages yellow. Api- 

 cal ventral angles of segments 3-8 with a black spot. (See also figs. 

 171-173.) 



Female. — Colored similarly to the male but some of the females have 

 black on the mesiiifraepistemum greatly reduced or in one specimen 

 even lacking. Usually the spots in the apical ventral angles of seg- 

 ments 3-8 are detached. (Vulva, fig. 174, occiput, fig. 175.) 



In some specimens of both sexes the two parts of the humeral stripe 

 are separated for their entire length. Such, while resembhng neva- 

 densis, never have the black stripes as narrow (see figs. 176 and 184). 

 This species differs from the other western species in its intense var- 

 nished appearance due to the scanty pile. 



Abdomen, male, 35-36 mm.; female, 36-37.5; hind wing, male, 

 28-30 mm; female, 32-33. 



This is the only species of OjMogomplius I have found in the 

 Transition and Canadian Zones. It occurred in Oregon on the Big 

 Meadows of the Deschutes, 18 miles south of Bend, which lie at an 

 elevation of about 4,000 feet. Here it was associated with northern 

 species such as occur at sea level in northern Washington or southern 

 Canada. On Lake Tahoe, which has an elevation of 6,000 feet, on 

 August 1, I collected a single male of this species at the mouth of 

 Emerald Bay. In a week's collecting along the shores of the lake 

 this was the only specimen of OpJiiogomphus I saw. Collecting on 

 Tahoe may have been better at one time, for the Keclamation Service 

 has recently raised the lake level several feet by a dam across its 

 outlet, which has very evidently disturbed the littoral fauna. 



The place where morrisoni occurred in its greatest abundance was 

 on Donner Lake, which has an elevation of 5,000 feet, or 1,000 feet 

 lower than Lake Tahoe. Here it was associated with almost the 

 same series of northern forms as were found with it on the Big Meadows 

 in Oregon. Three distinct kinds of beaches occur aromid this lake. 

 At its western end is pure sand where Gomphus donneri occurs. 

 Along the northwest shore is a series of gravel beaches which are 

 gradually displaced, as one passes toward the east end of the lake, 

 by cobble beaches. At the eastern end near the outlet, gravel occurs 

 again. OphiogompJius morrisoni is found on these gravel beaches. 



The males rest on the cobblestones scattered over the gravel or 

 pursue each other in zigzag flights along the lake shore. The females 

 are not as numerous and are usually found seated on stones very 

 close to the edge of the water. Here the males find them and take 



