The words eś and irec are the substitutes of ṭa and jha respectively in the liṭ (Perfect Tense).,
The श् of एश् indicates that it replaces the whole of the affix त 1.1.55. The च् of इरेच् is for the sake of accent (VI. I. 165). Thus पेचे, पेचाते पेचिरे । See the foregoing table of tenses for the Atmanepada.,