Way back when I was in high school, these were very common in a several-acre pine barrens area at the intersection of the old MD Route 3 and Benfield Boulevard. Most were green but sometimes you could see blue and black ones as well (see also Photo#1174239). Unfortunately, the habitat was obliterated with the construction of interstate 97 and an office "park" that now sits on the old site. If my memory is correct, these are the coordinates of the old pine barrens: 39.0938, -76.6280