These wasps are not single-celled organisms though, and their brains alone contain 4600 neurons. For reference, the brain of a honeybee contains ~1 million neurons. Despite their extremely small heads (again, look at that head next to the SINGLE CELLED amoeba) the wasps can still fly, seek out mates, and find thrip eggs to parasitize. So…what? How?
Phragma means a divider. My guess is someone was saying these tiny bugs are extremely (mega) separate (phragma) from their relatives.