About Megarhyssa nortoni (Cresson, 1864)
Megarhyssa nortoni has a body patterned black, reddish brown, and yellow, with distinct round yellow spots running down the side of its abdomen. Most of its legs are yellow, its wings are transparent, and its elongated body reaches 1.4 inches (36 mm) in length. Females are distinguished by an ovipositor that measures between 2 inches (51 mm) and 3 inches (76 mm) long. Males are less colorful and lack an ovipositor entirely.
This species is native to North America, occurring in parts of both the United States and Canada. The recognized subspecies have separate native ranges: M. nortoni nortoni is distributed in western North America, stretching from the Pacific Coast to Colorado, while M. nortoni quebecensis is found in eastern North America, across the northeastern United States and southeastern Canada. M. nortoni inhabits coniferous forests where horntail larvae live. It has also been intentionally introduced to Australia, New Zealand, Tasmania, Brazil, and South Africa for the biological control of horntail forest pests.
