Family: Siricidae, Horntails view all from this family

Description 1-1 1/2" (25-38 mm). Cylindrical. Dark red to black, abdomen marked with yellowish crossbands. Wings dusky to yellowish. Female has blunt ovipositor 1/4 as long as body, yellowish. Both sexes have horny, spearlike plate at tip of abdomen.

Food Adult drinks nectar. Larva eats fungus-infected wood of elm, beech, maple, oak, and other deciduous trees.

Life Cycle Female uses ovipositor to bore through bark into wood, depositing 1 slender egg in each hole. Eggs are covered with fungal spores from a special pocket in female's abdomen. As embryos prepare to hatch, fungi begin to grow and soften wood. Larvae tunnel into infected wood, making cylindrical passageways into side branches. They feed for up to 2 years, then pupate under bark in cocoons made of silk and wood chips. Adults are active in fall.

Habitat Hardwood and mixed forests.

Range Eastern North America.

Discussion After depositing the last egg, the female often dies without removing its ovipositor from the wood. The dead female becomes food for some insectivorous animal. Some ichneumon species, which parasitize and kill horntail larvae, are helpful in biological control of Pigeon Horntails. There are about 22 Tremex species worldwide but only 1 in North America.