Bembidion transversale

Description

Bembidion mannerheimii is one of the beetles in thesubfamily (Trechinae) in the family group running beetle. The systematics within the genus Bembidion is unclear, some divide the genus into several genera, while others place the species in subgenera. Bembidion mannerheimii is found in almost all of Europe, east to Belarus. It is also registered from Norway. Bembidion mannerheimii is a small beetle with a rather slender and slightly flat body shape. The antenna joints have long hairbrushes in the tip, the fourth part of the antenna has nice short adjacent hairs. (Requires magnification to see), The facet eyes are somewhat protruding. The maxillary palps have a small and needle-shaped end joint, this distinguishes the genus from the other Nordic running beetles, where this joint is much larger and more ax-shaped. Many of the species in the genus Bembidion are similar to each other and are difficult to determine species. Bembidion mannerheimii belongs to the group of insects with complete transformation (holometabolic insects), which undergo a metamorphosis during development. The larvae are radically different from the adults, both in lifestyle and in physique. Between the larval stage and the adult stage is a pupal stage, a resting period in which the internal and external organs of the beetle change. Bembidion is the largest genus of beetles in the family Carabidae by number of species. All species are small (less than 7.5 mm) and move very fast. Most of them live close to water. The genus has a biantitropical distribution, meaning they are found in both the Northern and Southern Hemispheres, but not in the tropics. In warmer regions it is substituted by closely related Tachys and other genera. There have been many attempts to divide it into smaller genera, most notably by René Jeannel in 1941 and by G.G. Perrault in 1981, but none of them have been generally accepted.