This is the first instar larva of the sheep nasal bot fly, Oestrus ovis. It was collected from the eye of a human patient in California (other information not available). Oestrus ovis presents as 1st instar larvae in the human host, usually manifesting as ophthalmomyiasis (ocular myiasis), rarely upper respiratory infection.

I have had this image for a while, but it was used for proficiency testing, so I had to wait until testing was completed before I could load to BugGuide.