In a recent paper (Goble and Dougherty, 1943) the incidence and identity of the lungworms in Varying hares in eastern North America was discussed. The nematode described as Synthetocaulus leporis by Boughton (1932) was re-described and renamed Protostrongylus boughtoni. Four subspecies of Lepus americanus Erxleben were listed as hosts of this parasite in eastern United States and Canada. Incidences observed from 1939 through 1942 ranged from 11 per cent in animals from New Brunswick to 48 per cent in those from Dickinson township in the Adirondack region. It is the purpose of this article to report further observations on P. boughtoni, made in New York during 1943, and to comment on Scott's (1943) recent article on lungworms in North American leporids.