[1] It is given its English name because of the elaborate pattern of black, orange-red and greenish-yellow markings in both sexes;[1][2] despite this the beetle is quite well-camouflaged when perched on a lichen or fungus covered tree trunk.

[3] The species name longimanus is a Latin word that refers to the extremely long forelegs (manus) of the large males, which are longer than the beetle's entire body.

Recent authorities have often considered Acrocinini as monotypic, but an analysis of morphological characters indicates that Macropophora and Oreodera are sufficiently close to also be included in this tribe.

[4][16] Male and female harlequin beetles have similar color patterns and reach a similar body size, but the species is sexually dimorphic in the foreleg length and shape: In large males, the forelegs are greatly extended, up to 15 cm (6 in) long, being twice the length as in females with the same body size.

[18] Harlequin beetles mainly fly during the night and appear to be able to rapidly locate recently fallen trees through the smell of the large amounts of sap that is released when it happens.

[16][18] When using trees that are still alive, they are occasionally regarded as a pest,[14][19] but otherwise harlequin beetles play an important role in the early phase of decomposition of dead wood, also creating habitats for other saproxylic species.

[15] Although the harlequin beetle is very rarely maintained in captivity, it has been successfully raised and bred for several generations using either freshly cut wood from Morus (mulberry), or an artificially composite of Morus sawdust, a commercial mixture used for insect rearing and morin suspended in agar, as a larval food source.

[20] The adult beetles can live up to about half a year, and they will feed on sap, wood, fungi and occasionally animal droppings.

At that point, pseudoscorpions from the colony will attach themselves to the emerging beetles to be transported to a new recently fallen tree, starting the cycle over again.