According to Devala, a Srotriya is one who is born as a BrAhmaNa , who has duly performed all the samskAras(Dvija) as ordained in the SAstras and one who is well-versed in the Vedic Scriptures (Vipra).
janmanA brAhmaNo jneya: samskArai: dvija ucyate!
vipratvam vidyayAcApi tribhi: Srotriya ucyate !!
---- Devala