Head of a European Hornet, Vespa crabro. To either side of the head are the large compound eyes consisting of thousands of individual units called ommatidia that produce a mosaic-like image. The three structures between the eyes, above centre, are the ocelli. These are light sensitive, and their function is thought to lie in the maintenance of stable flight. The European hornet is widespread throughout Europe, and is also now present in North America. Females are capable of delivering a painful sting, but in general hornets are not aggressive unless provoked. Like other Vespidae, they make a nest from chewed twigs and wood. Their diet consists of other large insects, including wasps, moths and bees; in late summer they are often to be found hunting near nectar sources such as flowering ivy (Hedera helix).