Insect identification by example
This is some species of Ground Beetle (family Carabidae); the trochanter of the hind leg (just before and somewhat overlapping the femur) and the threadlike antennae helps point to that group.  The book The beetles of northeastern North America by N. M. Downie and Ross H. Arnett (Sandhill Crane Press 1996; now out of print but in at least some libraries) may help with a species identification (fair warning: the keys are not profusely illustrated).