NO. 2107. DRAOONFLIES, WASHINOTON AND OREGON— KENNEDY. 315 



As the numbere of these Macromias were at their height on July 27 

 they probably had been on the wing three weeks, for they rapidly 

 disappeared after August 7, and none were seen after August 24. 



A short description of the Satus Creek region is given in my second 

 paper of this series (see pp. 269-270), but the following details may 

 serve to make more clear the habits of this species. Satus Creek, after 

 it emerges from Satus Canyon onto the Yakima River flats, is a cool 

 shallow stream of less than 10 second-feet, which meanders over long 

 gravel riffles from pool to pool. These pools are about 25 feet wide, 

 from 50 to 200 feet long, and, with few exceptions, are not over 4 feet 

 deep. They are gravel bottomed, except under high dirt banks, 

 where there is usually some mud, and are free from aquatic vegeta- 

 tion and brush, thus offering no protection to dragonfly nymphs, 

 except pools overhung by alders, where the alder roots form intricate 

 masses inhabited by lamprey eels, crayfish, and the nymphs of Agrion 

 aequabile ydkima, Aeshna umhrosa occidentalis, and Macromia. 



The male Macromias were usually found patrolling the larger pools 

 or sometimes a patrol would include two or three of the shorter pools. 

 Seldom were more than three or four males seen at any one time, and 

 each male's beat was rarely over 300 feet long. The flight was very 

 swift, ordinarily about 2 feet above the surface of the water and 

 straight down the middle of the pools or, on the broader pools, up one 

 side and down the other. For speed few dragonflies can equal it. 

 The speed was so great that even when I knew the passing dragonfly 

 was a Macromia, black with yellow spots, it appeared a uniform gi'ay ; 

 hence their confusion on the wing with Aeshnas. They were unu- 

 sually fearless and in the futile attempts to take them many times 

 dodged between the collector and the net. One even flew between 

 my legs. After much aggravation I found that by wading into the 

 deeper parts of a pool and facing a dirt bank not less than 5 feet high 

 so as to leave a passageway of about 4 feet for the patrolling Macro- 

 mias, occasionally one could be netted, for the nearness of the over- 

 hanging bank seemed to make them fear to dodge. They were 

 perhaps a little more easily taken when struck at from the rear than 

 when coming head on into the net, for when coming head on and 

 fairly in the net, before the collector could twist it shut they would 

 bounce back and out, apparently rebounding by some trick of the 

 wing on the cushion of dead air in the net.^ 



This species was found most commonly over the water on calm days 

 between the morning hours of 7 and 10. Few were found in the after- 

 noons or on windy days. The flight over the water appeared to be 

 controlled by the ovipositing females, who resorted to the water to 

 oviposit early in the day in calm weather, where they were sought 



'I have since found this species common on the larger -warmer streams of California and Nevada and 

 in some places rather easily captured. 



