The affix ñya is added without changing the connotation, to a word denoting a horde, but not when the word is derived from the name of their leader.,
The anuvritti of इव ceases. The word पूग means a crowd of men of various castes, having no fixed livelihood, connected together with the object of acquiring wealth &c. Thus लौहध्वज्यः 'the trident bannered horde'. dual लौहध्वज्यौ, pl. लौहध्वजाः ॥ Similarly, शैब्यः, शैब्यौ, शिबयः, चातक्यः, चातक्यौ, चातकाः ॥ In the plural, the affix is elided by 2.4.62.
Why do we say अग्रामणीपूर्वात् ? Observe देवदत्तकाः 5.2.78 'a horde whose leader is Devadatta'. From this sutra commence the तद्राज affixes &c, the affixes that have the sense of 'King thereof'. The affix ञ्य, therefore, has this meaning also viz. 'the leader of the horde'.,