Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Genus Megastigmus

parasitic wasp-Megastigmus aculeatus? - Megastigmus Torymid male? - Megastigmus Chalcid wasp- maybe Megastigmus? - Megastigmus spermotrophus - female  Megastigmus - Megastigmus - female Megastigmidae, from native roses - Megastigmus - male - female Chalcid wasp - Megastigmus - female Parasitic Apocrita? - Megastigmus - female Small wasp? - Megastigmus
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon ("Parasitica" (parasitic Apocrita))
Superfamily Chalcidoidea (Chalcid Wasps)
Family Megastigmidae
Genus Megastigmus
Explanation of Names
Megastigmus Dalman 1820
Greek mega 'big' + stigma 'mark, spot'
~30 spp. in our area, ~140 spp. worldwide(1)
Wings have relatively large stigmata (black spots) beyond middle of leading other respects, as in all chalcidoids, wing venation is extremely reduced (i.e. no closed cells). In females, long ovipositors are also present as in other torymid genera.
the Nearctic members of the genus are believed to be exclusively phytophagous, each larva feeding within a single seed of its host plant(2). Larvae of some species feed in conifer seeds, others in rose hips and other rosaceous fruits; M. pistaciae (introduced in CA) develops in pistachio nuts.
Print References
Milliron H.E. (1949) Taxonomic and biological investigations in the genus Megastigmus with particular reference to the taxonomy of the nearctic species (Hymenoptera: Chalcidoidea; Callimomidae). American Midland Naturalist 41(2): 257-420.
Works Cited
1.Universal Chalcidoidea Database
2.Annotated Keys to the Genera of Nearctic Chalcidoidea (Hymenoptera)
Gary A. Gibson, James B. Woolley, John T. Huber. 1997. Canadian Government Publishing.
3.Cone and seed insects of western forest trees
F.P. Keen. 1958. USDA Tech. Bull. 1169: vi+168 pp.