Trechinae
Four spot Ahlen runners ( Bembidion quadrimaculatum )
The Trechinae are a very large, globally widespread subfamily of ground beetles ( Carabidae ), but is probably not monophyletic. In Europe in 2272 species and subspecies are known.
Features
The tarsi of the front legs are broadened often unilateral in the males towards the body. The Epimeron of the mesothorax is wide or narrow.
The larvae of Trechinae correspond to Build the basic plan of the higher developed ground beetles. Your body is slightly flattened and has parallel side edges. The head is roughly rectangular and has, at the sides of six eye point ( Ocelli ) which are arranged in two rows. In species that live in caves, their number is reduced. The thorax has a large pronotum and a nearly equal small meso-and metanotum. The latter two are keeled forward. The legs are slender and are in most genera with only a Claw equipped. The first to eighth abdominal segment is structurally almost identical. The tergites are keeled forward. The sternites consist of a large central plate and paired smaller, front, outer and inner Laterosterniten. The ninth abdominal segment is reduced and has grown together Sternitplatten. His tergite is fused with the Urogomphi. The tergite of the tenth abdominal segment is cylindrical and directed downward. The larvae of the tribes Apotomini, Melaenini and Cymbiotonini are so far unknown.
Way of life
The lifestyle of the different subgroups of Trechinae is very different.
Systematics and distribution
It is still unclear whether the tribes Patrobini, Broscini, Psydrini and the genus Apotomus should be attributed to the subfamily or not. The preliminary allocation of the tribes Melaenini and Cymbionotini is questionable.