Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Creno on Dec 16, 2017December 16th, 2017, 11:35 am EST
probably cannot be sure from this pic only. If you could clearly see the palps, a male limnephilid has 3 palpal segments while the female has 5. I cannot see the palpal segments clearly in this specimen. Since Bob Newell took this pic it is likely he kept the specimen and could look at it with a microscope or other magnification. The females of Hesperophylax are easily separated to species based on their genitalia. Alot easier than the males.