Description & Statistics
Mason (1993) reported that the Megalyridae are mainly parasitoids of Coleoptera larvae that are found under tree bark. One species parasitizes a species of Pemphredonidae. There are about 11 species in Africa, South America, southeast Asia and Australia.
The body is sturdy and cylindrical (Mason 1993). The gena has a large, spacious, oval pit where the antennal scape occurs. The mesoscutum is flattened and has large triangular axillae, and in most but one genus there is a pronounced median groove that bisects the mesoscutum.
There has been indecision on the definition of this family. Species now placed in Megalyridae have been classified into as many as six other families (Braconidae, Evaniidae, Ichneumonidae, Stephanidae, as well as Dinapsidae and Maimetshidae.
The species are distinguished by the fact that their mesothoracic spiracle has moved, and is located in the upper corner of the pronotum, though this is a difficult feature to see. A useful character is that the base of the antenna fits into a wide concave groove below the eye. Females of Megalyra have ovipositors ranging from 5-8.3 times the body length, but this is not true of the other genera.
The largest known species is the female of the Australian Megalyra shuckardi, with a body length of 25 mm and ovipositor length of 83 mm. The smallest known megalyrid is the Brazilian Cryptalyra plaumanni, with a body length of 2.7 mm and ovipositor 1.2 mm long.
Megalyrid wasps are believed to be idiobiont endoparasitoids of concealed insect larvae. One Australian species, Megalyra troglodytes, attacks the larvae of Arpactophilus mimi, a mud-nesting crabronid wasp. Oviposition is primitive, because they insert their ovipositor into pre-existing cavities, holes, or cracks, rather than drilling into the substrate as in other hosts.
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Perrichot, V. 2009: Long-tailed wasps (Hymenoptera: Megalyridae) from Cretaceous and Paleogene European amber. Paleontological contributions, (1)
Rasnitsyn, A.P. & D. J. Brothers. 2009. New genera and species of Maimetshidae (Hymenoptera: Stephanoidea s.l.) from the Turonian of Botswana, with comments on the status of the family. African Invertebrates 50 (1): 191-204.
Shaw, S. R. 1988: Carminator, a new genus of Megalyridae (Hymenoptera) from the Oriental and Australian regions, with a commentary on the definition of the family. Systematic entomology, 13: 101–113.
Shaw, S. R. 1990: Phylogeny and biogeography of the parasitoid wasp family Megalyridae (Hymenoptera). Journal of biogeography, 17: 569-581. [Errata: Journal of biogeography, 18: 470]
Vilhelmsen, L., V. Perrichot & S. R. Shaw. 2010: Past and present diversity and distribution in the parasitic wasp family Megalyridae (Hymenoptera). Systematic entomology, 35(4): 658-677.