Hornets are insects that are the largest eusocial wasps. Some species can reach up to 5.5 cm (2.2 in) in length. The true hornets make up the genus Vespa and are distinguished from other vespines by the width of the vertex (part of the head behind the eyes), which is proportionally larger in Vespa and by the anteriorly rounded gasters (the section of the abdomen behind the wasp waist). The best known species is the European hornet (Vespa crabro), about 2–3.5 cm in length, widely distributed throughout Europe, Russia, North America and Northeast Asia.

Boat crew members train on the waters of the Tonle Sap River on the morning of the first day of the Water Festival on November 13, 2016 in Phnom Penh, Cambodia. The yearly three-day Water Festival is one of the most important holidays in Cambodia and celebrates the end of the rainy season and the start of the rice harvesting. The Festival also coincides with the Tonle Sap river reversing course, which it does twice a year. Approximately 2 million people are expected to attend this year's festival, during which 259 boats and nearly 20,000 oarsmen will participate in the races. After a fatal stampede resulting in the death of some 353 people during the Water Festival in 2010, it has been cancelled four times over the past five years, with weather used as an official excuse. (Photo by Omar Havana/Getty Images)

Palestinian barber Ramadan Odwan styles and straightens the hair of a customer with fire at his salon in Rafah, in the southern Gaza Strip February 2, 2017. In Ramadan Odwan's barbershop in Gaza, hair isn't just blow-dried, it's blowtorch-dried. “People have gone crazy about it, many people are curious to go through the experience and they are not afraid”, he told Reuters. “People here love adventures”. (Photo by Ibraheem Abu Mustafa/Reuters)

In this file photo taken on Sunday, August 2, 2020, Sviatlana Tsikhanouskaya, candidate for the presidential elections greets people waving old Belarus flags during a meeting to show her support, in Brest, 326 km (203,7 miles) southwest of Minsk, Belarus. Belarus’ authoritarian President Alexander Lukashenko faces a perfect storm as he seeks a sixth term in the election held Sunday, Aug. 9, 2020 after 26 years in office. Mounting public discontent over the worsening economy and his government’s bungled handling of the coronavirus pandemic has fueled the largest opposition rallies since the Soviet collapse. (Photo by Sergei Grits/AP Photo)

Emergency workers save a shepherd dog from a beach during a forest fire on August 2, 2021 in Mugla, a Marmaris' district, as Turkey struggles against its deadliest wildfires in decades. A roaring blaze raced toward a Turkish thermal power plant and farmers herded panicked cattle toward the sea as wildfires that have killed eight people raged on for a seventh day. The nation of 84 million has been transfixed in horror as the most destructive wildfires in generations erase pristine forests and rich farmland across swaths of Turkey's Mediterranean and Aegean coasts. (Photo by AFP Photo/Stringer)

Satirical sculptures burn during the traditional Fallas festival in Valencia, Spain, on March 19, 2014. Every year the city celebrates the ancient “Las Fallas” fiesta, a noisy week that is full of fireworks and processions in honor of Saint Joseph that ends on midnight of March 19, burning large satiric figures displayed around the streets of the city. (Photo by Alberto Saiz/Associated Press)

A woman is led aside as her partner is detained by Ukrainian security forces for being aggressive at an army checkpoint in the southeastern port city of Mariupol, on May 11, 2014. Residents’ attitudes appear to have hardened considerably with the deaths of dozens of pro-Russian activists in the city of Odessa this month and with reports that troops fired at a crowd in Mariupol last week. (Photo by Marko Djurica/Reuters)

A woman walks through flood water during heavy downpour at a street in Genoa, Italy, 10 October 2014. At least one person died due to flooding after heavy rains caused the Bisagno river, which runs through Genoa city to overflow. Part of the city was in black-out with flooded streets and parked cars dragged away by the water's force. (Photo by Luca Zennaro/EPA)