Cogswell 1949 Cinclera mexicanus Aug.29 9:00 am. (Trinity River) Willow Creek, 400 ft., Humboldt Co., Calif. I collected an immature along the bouldery shore of the river here, which is mostly very exposed to the sun - shy, flowing as it does at this season in less than 1/4 of its winter flood stage bed. The stream is now perhaps 30-50 yards wide. Aug.30 3 mi. N Willow Creek, 700 ft., Humboldt Co., Calif. One was found roosting under the bridge across Coon Creek by our camp by Dr. Pearson. He captured it by hand & brought it into camp. We released it shortly afterward near its roosting site but it flew off upstream over streamside brush thickets) in the dark. Sep.1 Just at twilight one was seen under the same bridge. It flew up to the spaces on the concrete buttress at 1 end of the bridge (on 1 of which an old, partially destroyed nest of this species is located). A few seconds later it flew down again & foraged (?) up & down stream for a few feet, going underwater for as long as 15 seconds or paddling(?) swiftly along the surface with head lowered. Then it perched briefly on streamside rocks, bobbed a few times & flew back up under the bridge. This process was repeated many times, with the perch under the bridge varying in position - being sometimes on projecting bolts in the center of the bridge