The 2004 detection of the nonnative woodwasp Sirex noctilio F. (Hymenoptera: Siricidae) in New York (Hoebeke et al. 2005, Newsl. Mich. Entomol. Soc. 50: 24– 25) raised concerns of potential tree mortality in North America because S. noctilio has caused extensive mortality of pine trees in the Southern Hemisphere (Ciesla 2003, J. For. 101: 18–23). Unlike in the Southern Hemisphere, pine woodwasps and associated parasitoids are native to North America (Schiff et al. 2012, Can. J. Arthr. Ident. No. 21). Determining the phenology of native woodwasps in the United States should help to determine the susceptibility of native forests to invasion by S. noctilio.