Megarhyssa Ashmead, 1900

Khalaim, A. I., Ruíz-Cancino, E. & Coronado-Blanco, J. M., 2021, Darwin wasps (Hymenoptera: Ichneumonidae) of Mexico: subfamily Rhyssinae, Russian Entomological Journal 30 (3), pp. 305-313 : 311

Genus Megarhyssa Ashmead, 1900

Megarhyssa Ashmead, 1900: 368 (new name for Thalessa Holmgren, 1859 ). Type species: Ichneumon clauatus Fabricius, 1798 .

= Eurhyssa Derksen, 1941.

= Thalessa Holmgren, 1859 (name preoccupied by Adams, 1853).

REFERENCES. Rohwer, 1920: 425 [description; review of 4 Nearctic species; key]. Townes, Townes, 1960: 415 [description; review of 4 Nearctic species; key]. Townes, Townes, 1966: 38 [catalogue; 1 species in Neotropical region; 1 species in Mexico]. Townes, 1969: 139 [description; remarks]. Carlson, 1979: 353 [catalogue; 4 species in America north of Mexico]. Ruíz-Cancino et al., 2002: 646 [checklist; 1 species in Mexico]. Kasparyan, 2002 [1 new species from Mexico ( Mexico)]. Khalaim, Ruíz-Cancino, 2013 [review of 3 species from Mexico (1 described as new); key]. Pook et al., 2016 [key to 4 Nearctic species].

The genus Megarhyssa comprises 37 species occurring predominantly in the Holarctic and Oriental regions, with most species in tropical Asia [ Kasparyan, 2002]. Four species occur in the USA and Canada, and one of them, M. macrurus ( Linnaeus, 1771) , is also known from northern Mexico. Two more species, M. verae Kasparyan, 2002 and M. gratiosa Khalaim et Ruíz-Cancino, 2013 , were recently described from central and southern Mexico [ Kasparyan, 2002; Khalaim, Ruíz-Cancino, 2013]. In Mexico, the genus is very rarely collected, but in the USA and Canada it seems to be more abundant in forests.

Species of Megarhyssa are idiobiont ectoparasitoids of xylophagous sawflies of the family Siricidae ( Hymenoptera ) on deciduous and sometimes on coniferous trees.