Hadith.2703 - Aban narrated from Abu al-Jarud, who said: A man asked Abu Ja'far عليه السلام about a person in the state of ihram who killed a louse.
Imam عليه السلام said: "What a bad thing he has done."
The man asked: "What is its expiation?"
Imam عليه السلام replied: "There is no expiation for it."