A. Laine, J. Itamies & M. Orell 1993: The Psocoptera of Norway Spruce (Picea abies) Branches in Northern Finland. - Entomologica Fennica 4: 201-206.
The psocid fauna living on spruce branches was studied in northern Finland, both in urban areas near the industrial city of Oulu and in rural surroundings, during the years 1986-88. Samples of about 6000 psocids of 19 species were taken from old and young spruces. The psocid assemblage of the rural area of Taivalkoski differed significantly from other areas according to the pooled data of old spruces. Mesopsocus unipunctatus (Muller), Caecilius burmeisteri Brauer and Trichadenotecnum majus (Kolbe) were most numerous in the most urban areas, Reuterella helvimacula (Enderlein) in the areas characterized by the epiphytic lichen Hypogymnia physodes.