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Dahlbominus Hincks, 1945 comparative info return to: prev home
Eyes minutely setose. Mandibles barely meeting medially. Clypeal margin truncate to very weakly bilobed. Flagellar formula 1,4,2 or 1,3,3 in both sexes; flagellum strongly compressed and broadening apically in females; basal 3 funicular segments with branches in males. Notauli incomplete; half of dorsal axillar surface advanced beyond scutellar margin. Postmarginal vein at most 1.7x stigmal vein length; forewing disc almost always with large, uniform fuscate area posterior to marginal and postmarginal veins [lost in some specimens]; uncus usually separated by more than its own length from stigmal apex [some specimens have a reduced stigma]. Propodeum with complete, though weak, median carina, without plicae. Scape, mesocoxa, and metacoxa usually light tan to white [sometimes light brown, especially in males]. Compare with: Sympiesis, Necremnus, Dicladocerus.

2a: Dahlbominus female, lateral view

3a: Dahlbominus forewing

4a: Dahlbominus dorsal view of mesosoma

Biology: Pupal ectoparasitoids of Diprionids.

Comments: Dahlbominus fuscipennis (Zetterstedt), the single described species of Dahlbominus, is an interesting species phylogenetically, as it may give clues to the relationships of Necremnus and Sympiesis. It is actually easily recognized using a reference collection, but potentially confusing to workers who have not seen it before, due to the lack of accurate taxonomic literature regarding it. I have seen some southern African specimens that may represent undescribed species of this genus.

Comparative information:

Sympiesis: Postmarginal vein 2x stigmal vein length or longer. Propodeum often without median carina, sometimes with plicae. Some species are similarly colored to D. fuscipennis (white coxae), but the postmarginal vein and propodeum distinguish them easily. Certain other species, especially some known from Florida, are very difficult to distinguish from D. fuscipennis because of their short postmarginal vein and similar body form. They differ mainly by the short stigma, coloration, and lack of fuscate cloud on the forewing.

Necremnus: Females always with 3 funicular segments. Scape, mesocoxae, and metacoxae not whitish,  forewing rarely with a similar fuscate cloud, uncus in some species separated from stigmal apex by less than its own length (unfortunately the best characters, other than association with females, for distinguishing males). Necremnus californicus (Girault) is very similar to D. fuscipennis in body shape and forewing features, but differs in the other characters listed above.

Dicladocerus: Females always with 3 funicular segments. Males with only 2 flagellar branches. Most species with parallel scutellar grooves. Coloration never similar. Body more elongate as a rule. Forewing without large fuscate cloud.

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References

Askew, R.R. 1968. Hymenoptera 2. Chalcidoidea section (b). Handbooks for the Identification of British Insects. 8(2)b.

Boucek, Z. 1959. A study of central European Eulophidae, 1: Eulophinae (Hymenoptera). Acta Entomologica Musei Nationalis Pragae. 33: 117-170.

Erdös, J. 1951. Eulophidae novae. Acta Biologica Academiae Scientiarum Hungaricae. 2: 169-237.

Schauff, M.E., J. LaSalle, & L.D. Coote. 1997. Chapter 10. Eulophidae. in "Annotated Keys to the Genera of Nearctic Chalcidoidea (Hymenoptera)". G.A.P. Gibson & J.T. Huber, eds. NRC Research Press, Ottawa.

Image credits: 1a: Erdös (1951). 1b: Schauff, et al. (1997).