558 PROCEEDINGS OF THE NATIONAL MUSEUM. 



or more would apparently remember the river and would spend sev- 

 eral minutes in a zigzag flight over its surface, returning shortly to 

 rest again on the willows. Several pairs in copulation were seen 

 flying about these thickets. 



This variety, except for its slightly greater size, is identical with 

 olivaceus of Cahfornia in structure, but is readily distinguished, 

 especially in fresh material, by the color, which is in general much 

 lighter than in the California specimens. In the field I did not doubt 

 that the two were distinct species, but was surprised when on my 

 return I studied them under a binocular and could find no constant 

 structural differences. The following are the hve color notes: 



Male. — Eyes blue, grayer below. General body color much more 

 yellow than the California specimens, thus giving the Humboldt vari- 

 ety a lemon or gray yellow appearance, rather than the dark gray 

 appearance of the former. Also all markings are more restricted 

 and paler. Thoracic markings medium to light brown. Humeral 

 stripe divided lengthwise into three distinct stripes by two inclosed 

 pale stripes. In perhaps one-third of the material the humeral stripe 

 fades out below. The black dorsal stripe on the femur reduced to a 

 spot on the distal half or third. Pterostigmas in male and female 

 pale gray yellow. In the abdominal markings segments 3-7 have a 

 broad yellow basal ring. The lateral spots are absent except on seg- 

 ment 7, where they are much reduced in size. Segment 10 in male is 

 mottled with brown above, and in the female is yellow, except for its 

 brown dorso-caudal edge. (See figs. 252-253.) 



Several exuviae, probably of this species, were found on the large 

 salt grass sods lying in the edge of the water where the banks had been 

 undermined. These will be described later. (See p. 570.) 



The following are the measurements of 8 males and 7 females from 

 Lovelocks: Male, abdomen, 40-42 mm.; hind wing, 33-34; female, 

 abdomen, 40-43 mm; hind wing, 34-36. 



GOMPHUS SOBRINUS Selys. 



Gomphus sohrinus has been known heretofore only from the type, a 

 single male specimen "collected by Edwards in California" and later 

 deposited in McLachlan's collection. This was described by Selys 

 in the year 1873 in his Third Addition to the S^Tiopsis of the 

 Gomphines. 



Except for the above specimen the species has remained unknown 

 until this year. In April of this year I took a single specimen, a 

 female, on Felt Pond on the Stanford campus, and in May I found 

 it very abundant on Coyote Creek within the city limits of San Jose, 

 where in a single day's collecting I succeeded in taking over 50 speci- 

 mens, though much of the time was spent in endeavoring to catch 

 Macromia. During the fore part of June I took several specimens 



