First record of the genus Lamachus Förster, 1869 (Hymenoptera: Ctenopelmatinae) from Mexico, with description of two new species.
Two new species of the genus Lamachus Förster, 1869, L. cushmani Khalaim et Ruíz-Cancino, sp.n. and L. toluca Khalaim et Ruíz-Cancino, sp.n., are described from Central Mexico. The genus Lamachus, as well as the tribe Mesoleiini, is recorded from Mexico for the first time, representing a southern most record of the genus in the New World. A checklist of eleven North American species of Lamachus, including eight native and three introduced species, is provided. An identification keys to species of Lamachus occurring in Mexico is given. Neodiprion omosus Smith (Diprionidae) is reported as a host of Lamachus species for the first time.