Electron carrier between complex III (ubiquinol-cytochrome c oxireductase) and complex IV (cytochrome c oxidase). E(0) is +248 mV. Loosely associated with the inner membrane. Found in the mitochondria from unembryonated eggs, and in second-, third-, and fourth-stage larvae. Highest expression found in second-stage larvae. Reaches undetectable levels in the adult. Binds 1 heme c group covalently per subunit. Belongs to the cytochrome c family. Life shuttle - Issue 76 of November 2006