Horntail

Horntail or wood wasp is the common name for any of the 150 non-social species of the family Siricidae, of the order Hymenoptera, a type of xylophagous sawfly. This family was, until recently, believed to be the sole living representative of the superfamily Siricoidea, a group well represented in Paleogene and Mesozoic times, but the family Anaxyelidae has recently been linked to this group. The last tergite of the abdomen has a strong, projecting spike, thus giving the group its common name (the ovipositor is typically longer and also projects posteriorly, but it is not the source of the name). A typical adult horntail is brown, blue, or black with yellow parts, and may often reach up to 4 cm long. The pigeon horntail (Tremex columba) can grow up to 5 cm long (not counting the ovipositor), among the longest of all Hymenoptera.