The soldier beetles, Cantharidae, are relatively soft-bodied, straight sided beetles, related to the Lampyridae or firefly family, but being unable to produce light. They are cosmopolitan in distribution. One common British species is bright red, reminding people of the red coats of soldiers, hence the common name. A secondary common name is leatherwing, obtained from the texture of the wing covers.
Historically, these beetles were placed in a superfamily "Cantharoidea", which has been subsumed by the superfamily Elateroidea; the name is still sometimes used as a rankless grouping, including the families Cantharidae, Drilidae, Lampyridae, Lycidae, Omalisidae, Omethidae, Phengodidae (which includes Telegeusidae), and Rhagophthalmidae.
Soldier beetles are highly desired by gardeners as biological control agents of a number of pest insects. The larvae tend to be dark brown or gray, slender and wormlike with a rippled appearance due to pronounced segmentation. They consume grasshopper eggs, aphids, caterpillars and other soft bodied insects, most of which are pests.
The adults are especially important predators of aphids. They supplement their diet with nectar and pollen and can be minor pollinators. Soldier beetle populations can be increased by planting good nectar- or pollen-producing plants such as Asclepias or Solidago.