An affix comes after a word in the Locative -7th case in construction denoting time, in the sense of 'who then wanders' and the word so formed refers to a wild beast.,
Thus निशायां व्याहरति मृगः \an animal that wanders at night.\ So also प्रादोषः or प्रादोषिकः 4.3.14 'a brute that yells in the morning.'
Why do we say मृगः 'a beast' ? Observe निशायां व्याहरति उलूकः ॥ Here there is no affixing. The word व्याहरति also means 'to make noise.' The Sutra may, therefore, also be translated as : \After a word denoting time, an affix 4.1.83 comes in expressing a wild beast who makes noise at that time\.,