542 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.62. 



My o^vn records and those in the Stanford collection and in Mr. 

 Grinnell's collection are all for May and June. The records are for 

 Chico, Butte County; Napa River, Napa County; Oroville in an irri- 

 gation ditch; Walnut Creek, Contra Costa County; Los Gatos and 

 Stevens Creek, Santa Clara County; San Lorenzo River, Santa Cruz 

 County. This last is Selys's type locality. 



A'liss Butler has described this species as sequoiarum.^ Her types 

 are three specimens collected by Dr. J. C. Bradley at Three Rivers, 

 Tulare County, Cahfornia, July 16, 1907. This place has an eleva- 

 tion of 500 feet. Prof. J. G. Needham ^ records nymphs from Lake 

 Tahoe, elevation 6,000 feet; I doubt that they are correctly labeled. 

 I did not see this species on Lake Tahoe myseK. 



OPHIOGOMPHUS OCCIDENTIS Hagen. 



Live colors, male. — Thorax green, abdomen yellow, markhigs dark 

 brown. (See fig. 204.) 



Face greenish yellow; vertex black with the postocellar ridge 

 yellow; occiput yellow; eyes gray. 



Thorax green on the sides, whitish below, with a middorsal brown 

 stripe which is 1.5 ram. wide below and narrower above, or even ter- 

 minating in a point at the antealar sinus. Only the extreme edge of 

 the antealar ridge brown. A broad humeral stripe tliree-fourths the 

 width of which lies anterior to the suture; this stripe, 1.5 mm. wide 

 above and below, is sUghtly narrower in its middle third and usually 

 includes a fine line of pale green running lengthwise through its two 

 middle fom-ths. In most specimens a narrow (0.25 mm.) pale brown 

 line between the front wing and the mesepimeron, also one on the 

 second lateral suture which extends down around the metmfraepi- 

 stemum. Legs grayish white with an external (dorsal) black stripe 

 the entire length of the femur of the first pair and only on the distal 

 half of the second and third femora ; tibiae black with an external white 

 stripe; tarsi black. Costa yellow; pterostigmas dark gray to brovm. 



Abdomen rich yellow dorsally and on sides of segments 7-10, 

 but white on the sides of segments 1-6 below the black markings. 

 These markings are as follows: A band 1.5 mm. wide on the upper 

 half of side of segment 1 running caudad and meeting its mate of 

 the other side at the dorsal apex of segment 2. A small spot posterior 

 to auricle. A lateral black stripe about 1 mm. wide extending from 

 segments 3-9 ; on the apical third of each segment it widens dorsad, 

 extending to the middorsal line at the apex of the segment. A black 

 spot on the ventro-apical angle of the side of each of segments 3-8. 

 Segment 10 and appendages largely yellow. 



Female colored much like the male, but the lateral stripe on the 

 abdomen narrower and more broken, and the apical dorsal extensions 

 narrower. (Structural details: Male, figs. 205-208; female, 209-210.) 



1 Can. Ent., vol. 46, 1914, p. 346. » Proc. U. S. Nat. Mus., vol. 27, 1904, p. 690. 



