The structure and surface properties of the eggshell of Megaselia imitatrix Borgmeier (Diptera, Phoridae) in relation to the respiration of the embryo

The role of the chorion in the mechanism of respiration is examined for the egg of Megaselia imitatrix. An air layer in the chorion is not essential for respiration, and oxygen can be absorbed through a hydrophilic pathway in the chorion by diffusion from the surrounding water. A model based on the diffusion of oxygen through the surface layer of the water down to the depth of the egg is proposed and presented in detail.