Atlantic Horseshoe Crabs - Limulus polyphemus
Jones Beach State Park, Nassau County, New York, USA
June 15, 2017
At Short Beach Island. Note the pervert American Herring Gull (Larus argentatus smithsonianus) to the left.
Adds June for NY, Long Island for BugGuide
Sorry for the bad pictures; they were far away and I was using a 400mm lens the get them