Stag Beetle (Lucanus cervus) is our largest and most massive beetle. It is characterized by very conspicuous sexual dimorphism. Males grow up to a length of 90 mm. They have an unusually wide head and very well-developed mandibles, which constitute almost one third of the body length. The mandibles are toothed from the inside. Females have a considerably smaller head, narrower than the pronotum and shorter, less noticeable mandibles. They grow up to approximately 50 mm. Both sexes are similarly colour. The head, pronotum and legs are grey-black; the wing-cases are reddish brown.  The male mandibles are also reddish brown, whereas...