There seem to two regions or countries with the name Aśvaka, namely, one in the north-west, and the other in the south. Aśvaka, in the sense of one of the sixteen mahājanapadas, is said to be the one in the south. In Buddhist Pāli sources, it is called Assaka (CPD), and in Sanskrit sources it is called Aśmaka as well as Aśvaka (Gupta 1989: 17–19). See also MW (s.v. “N. of a people, … (cf. aśmaka).” The CPD does record the Sanskrit name Aśmaka but not Aśvaka (in the sense of the name of mahājanapada). A list of the sixteen mahājanapadas transmitted via the Tibetan translation of the *Vasiṣṭhasūtra (gNas ’jog gi mdo), translated by sKa ba dPal brtsegs, has already been noted by Dan Martin. The list has also been cited in dPal brtsegs’s gSung rab rin po che’i gtam. The difficulty with the list found in Tibetan sources is identifying the proper Sanskrit names behind those names translated into Tibetan or left un-translated or in partial phonetic transcription. One such name that poses a difficulty is “Sreg pa.” This is clearly a translation and not a phonetic transcription. In the *Vasiṣṭhasūtra (gNas ’jog gi mdo), it is spelled “Sreg pa,” whereas in the gSung rab rin po che’i gtam, it is spelled “Srag pa.” Of course, one should check all versions. I personally presume that the former is the correct reading and the latter corrupt. But the question it what could have been the Sanskrit name behind the Tibetan name and why has it been rendered thus? If we consult Negi’s dictionary, we see that “Aśmaka” has been rendered into Tibetan as “rDo can” (clearly as a name of country or mahājanapada). I surmise that “Sreg pa” is a rendering of Aśvaka. But is not Aśvaka supposed to mean something like “a small or bad horse” or “a toy-horse” (MW)? And what does the Tibetan sreg pa (here) mean? It turns out that sreg pa (according to Jäschke 1881) means a “partridge.” In the Tshig mzod chen mo (s.v. gong ma sreg), the bird is called bya sreg pa, a bird which is said to similar to a bya gong mo (also called lha bya gong mo or spang bya sreg pa). Some sources identify it to be a “grouse” (Jäschke 1881: s.v. gong mo). But can Aśvaka mean a certain kind of a bird? MW does state that Aśvaka also means a “sparrow” but as attested only in lexicons (L). But at least there seems to have been some basis why Tibetan translators translated Aśvaka here in the sense of a certain bird known in Tibetan as sreg pa. Old Tibetan documents (e.g. Pelliot tibétain 1285) do allude to bya’ sreg pa. In conclusion, I believe that I was able to plausibly explain that the Sanskrit name behind “Sreg pa,” as one of the sixteen mahājanapadas, could have well been Aśvaka.