Eggs of aquatic and terrestrial hairworms, light photomicrographs A egg of Gordius difficilis stained with Nile Blue; note the thin inner membrane (arrow) surrounding the larva B egg of Neochordodes occidentalis showing a thin inner membrane (arrow) surrounding the larva C egg of Paragordius obamai showing a developing larva surrounded by a thin inner membrane (arrow) D egg of Gordius terrestris sp. nov. showing a distinct thick inner membrane (arrow) surrounding the larva. Scale bars: 6 µm (A); 8 µm (B, C); 11 µm (D).