NO. 2192. DRAQ0NFLIE8, CALIFORNIA AND NEVADA— KENNEDY. 619 



40 miles long and 10 broad. It is saline with a density of 1.0034, 

 or about one-ninth that of sea water. It is a brilliant emerald green 

 body of water, surrounded by rugged brown hills barren of any 

 vegetation except sagebrush and the few desert plants that survive 

 the extreme aridity of this region. The only green vegetation is that 

 of the cottonwoods and alders in the delta of the Truckee River. 

 The only conspicuous life is that of the grotesque pelicans which 

 wade solemnly in single file along its beaches. 



It has been shown by R. C. Osburn ' that Odonata can not live 

 comfortably in a density of sea water much over 1.008. I found 

 the following four species breeding in the lake and the pools back of 

 the beach lino. 



1. ENALLAGMA CARUNCULATUM Morse. 



One male was found when I went over my Pyramid Lake material 

 carefully. (In my notes in the Anuals of the Entomological Society 

 of America^ I mentioned only two species in Pyramid Lake, Enallagma 

 clausum and Sympetrvrn. corruptum.) This species may breed in the 

 lake in very limited numbers or it may be from the Truckee Delta, 

 which w^as 1 mile west. This species is the most widely spread of 

 all the western species of Enallagma and an alkali pond species, so it 

 might be expected. 



2. ENALLAGMA CLAUSUM Morse. 



This bred in large numbers in the shallow edge of the lake. A 

 species of Potamogeton grows sparingly along the shore of the lake, 

 and to this are attached masses of filamentous algae. These masses 

 break loose and are washed along the beach in quantity. In this 

 litter two species of Odonata breed freely, Enallagma clausum and 

 Sympetrum corruptum. Through the wave action the beach at the 

 edge of the water is built into a low dyke over which storms force 

 high waves that make a series of algae-filled pools from which both 

 species emerge freely. Probably these individuals are washed into 

 these pools from the lake when the pools are formed. On fence 

 posts 50 feet from shore I found exuviae of both species. 



Enallagma clausum has habits of alighthig on the beach and flying 

 quickly along the surface of the ground which are much like those 

 of an Argia. Because of their nervous alertness and this habit of 

 hugging the ground they are very difficult to capture, though they 

 occm- in large numbers. Copulation is on the wing or while seated 

 on the beach or on the masses of algae. Emergence is at all hours, 

 as I saw fresh tenerals at 3 o'clock in the afternoon. The male holds 

 the female during oviposition while she places the eggs in the masses 

 of algae. 



3. ISCHNURA CERVULA Selye. 



One male was found among my material. 



1 Amer. Nat., vol. 40, 1906, p. 395. 



2 Ann. Ent. Soo. Amer., vol. 8, 1915, p. 297. 



