 Christii flies live under the bark of smaller branches or twigs of dead aspen trees.Iain Christie originally discovered the Christii fly with several others in the late 1980s, but the fly was not recognised as a new species until 1997, during a survey of the flora and fauna of the Cairngorms.The research was conducted for the book "The Nature Of The Cairngorms", which includes 223 species mainly found there and 1,153 further species for which the Cairngorms are nationally noted.