On reproduction and survival in two ecologically related beetle-species of the forest floor (Pterostichus oblongopunctatus (Fabricius) (Col., Carabidae) and Philonthus decorus (Gravenhorst) (Col., Staphylinidae)) / [by] Henricus Johannes Laurentius HeessenOn reproduction and survival in two ecologically related beetle-species of the forest floor : (Pterostichus oblongopunctatus (Fabricius)(Col.,Carabidae) and Philonthus decorus (Gravenhorst)(Col.,Staphylinidae)) / door Henricus Johannes Laurentius Heessen