334 PROCEEDINGS OF THE NATIOXAL MUSEUM. vol.49. 



lava field of several sections in extent, which has flowed down into 

 the Deschutes gorge damming the river so that its present bed is 500 

 or 600 feet above the primitive channel. The lake, which was formed 

 back of this dam, is now filled with sediment and forms the Big 

 Meadows. These lie at an elevation of 4,000 feet, and a frost had 

 occurred there on July 4. The Meadows are surrounded by yellow 

 and jack pine over the western rim of which rises the snow-capped 

 Bachelors Peak. Several shallow sloughs, which are fiUed by springs 

 and by high stages of the river, occur here and each is a favorite 

 resort of special species. 



I spent four days here (July 4-7) at the ranch of Mr. F. A. Shon- 

 quest, who helped me in various ways. The following is a list of the 

 species found : 



1. AGRION AEQUABILE (Say). 



One specimen was seen on the meadow near Mr. Shonquest's 

 meadow road. One, a female teneral, was taken just above the lava 

 dam (Denham Falls). At the tune I took this I thought it the variety 

 yakiina, but it has faded until now it is impossible to determine the 

 subspecies. As the numbers of aequahile reached their height later 

 than this on the warmer Satus Creek, Washuigton, I behevc this an 

 early date for the species here. 



2. LESTES UNCATUS Kirby. 



Very abundant in sedges along the river and in the first slough 

 across the river from Shonquest's. The adults are rich blue-green. 

 Breeding, but still emerging in large numbei-s. Though described 

 by Needham, because of the abundance of material I have figured the 

 nymph. 



Nymph (figs. 173-176). — Needham* has listed the nymph of Lestes 

 uncatus in a key to the species of Lestes, but he does not distinguish 

 it from the nymph of unguiculatus. Whether it can be distinguished 

 on further study I do not know, as I have no nymphs of unguiculatus. 

 But as I had excellent specimens of both nymphs and skins of uncatus 

 I have thought it best to figure this nymph, which differs in various 

 ways from the nymph of congener (figs. 168-172). 



This nymph is more slender than that of congener and considerably 

 larger. Its measurements are as follows: Head, 4 mm. wide, 2 mm. 

 long; length of head, thorax, and abdomen, 28; gills, 10 extra; abdo- 

 men, 13.5; hind femur, 5. 



In this species the folded labium (Hg. 175) is very slender, its hinge 

 reaching caudad beyond the metathoracic coxae (see figs. 173 and 176), 

 whereas in congener (figs. 168, 170, 171) it reaches barely to themeso- 

 thoracic coxae. The basal two- thirds of the mentum is almost triangu- 

 lar in outline. There are normally seven mental setae, though one 

 specimen had only six. There are two setae on the movable hook 



1 Needham, James 0., MacGillivraj', Alex. D., Johannsen, O. A., aiul Davis, K. C. Aqitatic Insects in 

 New York State. Bull. 68, N. Y. State Mus., pp. 517, pis. 52, text figs. 20, 1903. See p. 233. 



