Musannaf Ibn Abi Shaybah

Hazrat Abu Umamah narrates that I asked Hazrat Ibn Umar (may Allah be pleased with them): Can I kill a mosquito? He replied: Is there nothing upon you in return for that?

Hazrat Ubaidullah bin Abu Ziyad says that I saw Hazrat Salim kill a mosquito in Makkah. I asked him about this. He replied, "We have been commanded to kill snakes and scorpions." I said, "They are our enemies." He replied, "This too is an enemy."

Hazrat Ata says that there is no harm in killing a fly or a mosquito while in the state of Ihram.

Hazrat Saeed bin Jubair was asked: If a Muhrim kills a fly? He replied: There is nothing (no penalty) upon him.