Mature larva or puparium of a rodent bot fly

6308 Found this in my basement on a wooden shelf in Ottawa, end of August, what the heck is it? From Stittsville, ON

Number 6308 This is a mature larva or puparium of a rodent bot fly (Diptera: Oestridae; Cuterebra spp.). The larvae of these flies develop under the skin of their host, breathing through a hole they make in the skin. When ready to pupate, they enlarge the hole and emerge, then seek a sheltered place to undergo pupation and transform into the adult fly. Click here for more detailed information.