Springtails may be small, booklice and barklice are smaller still. Booklice for instance are present in most homes, but no one ever sees them. Booklice and Barklice are all very small insects showing a flattened body, a broad head and long, usually wirelike antennae. Many species remain wingless. Those species growing wings often look like very small plant lice. The veins runs very differently, though. Besides plant lice have needle shaped jaws, those of Psocoptera are made for biting. In many species males are unknown or very rare. Reproduction often does not require the presence of males (parthenogenetic). Most species will eat pollen, the spores of funghi or algae. On wood we will often find bark lice. Some are striking, because of their size. Barklice may cause damage on wood. In the days all ships were made out of wood, they were very feared among sailors.
The Bark Louse below most likely is Metylophorus nebulosus. It is a giant among the Psocoptera, for it will reach a length of 4mm, where most species hardly reach 1mm. It lives on the bark of shrubs and trees. It is found on both deciduous and coniferous trees. And not only in forests, but on isolated trees as well. Is found in enormous quantities on Norway Spruce. Like most barklice Metylophorus nebulosus eats lychens, algae and fungus spores it finds on the bark. This species is single-brooded. Lives in Europe, the moderate zone of Asia and Japan.