Macrosiagon ferruginea, : BEDEL, 1895

Batelka, Jan, 2011, Contribution to the synonymies, distributions, and bionomics of the Old World species of Macrosiagon (Coleoptera: Ripiphoridae), Acta Entomologica Musei Nationalis Pragae 51 (2), pp. 587-626 : 618

Macrosiagon ferruginea species group

Included species. M. ferruginea , M. signaticollis , M. carinicollis Fauvel, 1905 ( New Caledonia: Ile des Pins) and M. baeri Pic, 1906 ( Argentina) .

Diagnosis. All four species possess a narrow evagination in the posterior edge of the metepimeron, an apomorphy possibly developed to accomodate or support the apical edge of the metafemur.All four species are of the same morphotype but are distinguishable by their coloration.

Remarks. As far as I know, this peculiar modification of the metepimeron is developed only in two other Macrosiagon species : M. cruenta (Germar, 1824) (North and Central America) and M. multinotata Pic, 1906 (South America). My identification of M. multinotata is based on its type specimen, examined by myself in MNHN. However, in some collections, this species is labeled as M. gayi ( Gerstaecker, 1855) so these names may be synonymous. The relationship of M. cruenta and M. multinotata with the M. ferruginea species group is unclear. They are of a similar shape with elytra typical for the M. ferruginea species group, and M. cruenta shares the same host group with M. ferruginea (which is the only representative of M. ferruginea species group for which the biology is known). In all cases M. ferruginea was reported to develop in the nests of wasps of the subfamily Eumeninae ( BEQUAERT 1918, BÉTIS 1912, CHOBAUT 1891, FALIN 2004b, GRANDI 1936, HORNE & SMITH 1870, LONGAIR 2004, ROUBAUD 1916). Macrosiagon cruenta was also twice reared from eumenid nests ( GENARO 1996, SNELLING 1963). Some of the other Macrosiagon species in which this evagination is missing are also known to be exclusive parasitoids of Eumeninae , e.g. M. nasuta ( BATELKA & HOEHN 2007) , therefore the evagination in the posterior edge of metepimeron might be of phylogenetic rather than of ecological origin. It is possible that M. cruenta and M. multinotata also belong to M. ferruginea species group.