[3] The “Holz” in the German common name Holzbuntkäfer indicates that these checkered beetles are found in wood.

Although Tillus elongatus can reach up to a size of 1 cm long, the beetle is rarely seen by humans, as it primarily resides hidden in the wood of trees.

In contrast to most checkered beetles, Tillus elongatus is plainly coloured.

[7] The female, on the other hand, has a reddish brown pronotum and bluish black elytra.

[8] In rare cases, the base of the pronotum of the male is also completely or partially red.

The heat-loving species is found in old deciduous and mixed forests, as well as in parks.

They are usually found in forest edges or in clearcuts on sun-exposed trunks of hardwoods with insect infestation.

With the claws and two chitin hooks at the end of the body, the Tillus elongata larva can also work its way into larval tunnels blocked with debris from boring insects.

The larva can also bite its way into neighbouring tunnels with its mouthparts if the dividing walls are thin.

At night, the larva can leave the tunnel system and crawl into a distant emergence hole on the surface of the wood and thus occupy new passages.

Before pupation, the larva widens a dead end passage into a cradle for the pupa.