This cosy sheep nasal bot fly (Oestrus ovis) was found on the outside of a rural shed, Buckland, Tasmania.
Oestrus ovis is an introduced and widespread bot fly (family:Oestridae) being found throughout Australia. It's the only bot fly of the Oestridae family known to occur in Tasmania (click for oestrid bot flies in Aus.).
For info on the lifecyle of this species click here.
Though Oestrus ovis preferentially deposit their parasitic larvae on sheep, there are numerous cases of human parasitism in the many countries across the world where this species occurs. For an excellent medical paper that covers a recent case of an American soldier in Iraq plus a good overview of their biology click here (pdf) or here (html) (nb not for the squeamish).