Dead inside campground bathroom surrounded by mixed (oak, hickory, loblolly pine, sweet gum) sandy forest. Possibly had been attracted to light and then got trapped inside? Keyed out using George Ball's A Taxonomic Study Of The North American Licinini
Ball (1959) . The key is on page 104. In my experience these are much more common in Maryland than the somewhat similar
D. furvus. See notes under

for identification details.
Note: You must obtain a permit to collect insects in Maryland State Parks and State Forests.