Insects factored as ‘symbols of instinct’, necessary as a rhetorical device in the boundary work of early social psychology. They were symbolically used to draw a dividing line between humans and animals, clarifying views on instinct and consciousness. These debates were also waged to determine if social psychology was a subfield of sociology or psychology. The exchange between psychologist James Mark Baldwin and sociologist Charles Abram Ellwood exemplifies this particular aspect of boundary work. After providing a general background of the (...) debates, I turn specifically to the writings of Baldwin and Ellwood between 1890 and 1936, tracing the use of insects as ‘symbols of instinct’. (shrink)