as we all know, the classic skirmishers of the republican roman army was the velites recruited from the youngest and poorest of the citizenry of rome.

but with the marian reforms this structure changed, the various heavy infantry changes are well known and documented, similarly the cavalry and the like, but who filled the role of the light troops similar to what the velites held with javelins and a parma as opposed to more psiloi like troops with slings and short bows