588 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



water one by one to hunt insects in the simshine above on the hill- 

 tops. In the patroUing of the creek they combine feeding and hunt- 

 ing for females. A male will fly slowly along the rocky wall over- 

 hanging the water, inspecting every nook and cranny, and only give 

 a hurried inspection to the open side of each pool. After being satis- 

 fied that he has not overlooked a female he will rise over the water- 

 fall at the head of the pool and proceed to inspect, in the same 

 manner, the stream above. 



In a single afternoon's collecting I caught 14 males, which was 

 probably a half of aU living on the stream at the time, for in the next 

 two days males were so scarce that I took only two more. 



The females do not spend as much time on the creek as the males. 

 Few were found on the creek before 3 o'clock, but when it had be- 

 come almost twihght in the depths of the gorge they were nervously 

 hurrying up and down the creek ovipositing. The method of this 

 was so unusual that I did not recognize at first what they were doing. 

 A female would ahght on one of the rock walls overhanging a pool 

 and would try to insert her ovipositor in the rock. After an attempt 

 or two she would fly a few inches or feet and make another attempt. 

 As the rocks over the pools in the shadier spots were seamed with 

 Unes of green moss, she would soon locate such a seam and drive her 

 ovipositor into the vein of moss. The eggs thus were laid in the tliin 

 seam of moist earth which supported the moss. Usually less than a 

 half dozen stabs would be made in one seam when she would fly to 

 another and repeat the laying. In two places where tree roots hung 

 into the water, females were flushed that were probably ovipositing 

 in these. Oviposition was going on as late as 5 o'clock when it was 

 almost twilight in the shadier portions of the gorge. 



In copulation a male usually found a female while she was seated 

 on a vertical waU of rock, and picking her off the two would fly away 

 in copulation. This usually lasted some time while the pair hung 

 to some hve oak bush on the hillside. Pairs did not fly in couple as 

 does Anax. 



The nymphs were abundant in the shallow algae-fiUed pools, where 

 they crawled slowly under and over the masses of green algae. One 

 was observed eating a small tadpole of which there were many of at 

 least two species in the stream. 



This remarkable Aeshna, which is probably one of the last to be 

 described from north of Mexico, I take pleasure in naming for Dr. 

 E. M. Walker, who in his beautiful monogTaph of the North Ameri- 

 can species of tliis group has opened the way for future students. 



AESHNA WALKERI, new species. 



Length of abdomen, including appendages: Male (Palo Alto, Cali- 

 fornia), 51-57 mm.; female (Santa Cruz Island, Cahfornia), 56. Fe- 

 male appendages, 6 mm. Hind wing: Male, 43-47 mm.; female, 48. 



