Pipistrelles proper: little bats that glide, sing, swarm and lek (vesper bats part XVIII)
Among the best known, most widespread and most familiar of vesper bats are the pipistrelles. All bats conventionally regarded as pipistrelles are small (ranging from 3-20 g and 35-62 mm in head-body length), typically with proportionally short, broad-based ears and a jerky, rather erratic flying style.
Source: scienceblogs.com