Myzinum Latreille

Kimsey, Lynn S., 2009, Taxonomic purgatory: Sorting out the wasp genus Myzinum Latreille in North America (Hymenoptera, Tiphiidae, Myzininae), Zootaxa 2224, pp. 30-50 : 32-33

Myzinum Latreille

Myzinum Latreille 1803:326 . Type species: Tiphia maculatum Fabricius 1793:224 . Monotypic.

Myzine Latreille 1805 (1804) :269. Invalid emendation of Myzinum Latreille 1803 .

Elis Fabricius 1805:248 . Type species: Elis sexcincta Fabricius 1775:356 . Designated by Bingham 1897. Synonymized by Illiger 1807.

Plesia Jurine 1807:150 . Type species: Tiphia namea Fabricius 1805:233 . Designated by Ashmead 1903.

Myzina (!) Rafinesque-Schmaltz 1815:124. Invalid emendation of Myzinum Latreille 1803 .

Gonordula Argaman 1994:87. Type species: Myzine lateralis Cresson 1865 . Synonymized by Bartalucci 2004.

Cocovasna Argaman 1994:86. Myzine flavopicta Smith 1855 . Original designation. Synonymized by Bartalucci 2004.

Keyovaska Argaman 1994:88. Type species: Myzine frontalis Cresson 1875 . Synonymized by Bartalucci 2004.

Tokoparta Argaman 1994:88. Type species: Plesia sexmaculata Guérin Méneville 1838 . New synonymy.

Fikoplesa Argaman 1994:88. Type species: Myzine elegans Burmeister 1876 . New synonymy.

Ekepirka Argaman 1994:88. Type species: Myzine robusta Burmeister 1876 . New synonymy.

Male.―Body length 7–24 mm; body long, slender, black with yellow markings; legs black, black and yellow or red; clypeus strongly convex, apical margin shallowly emarginated; inner eye margin notched or strongly emarginate; mandible with single subapical tooth; genal bridge usually strongly protruding forming obtuse to acute angle; flagellum elongate, cylindrical, flagellomeres longer than broad; legs slender; apical metasomal sternum forming long slender, upwardly curved uncus; apical metasomal tergum apically bidentate or medially notched.

Female.―Body length 8–23 mm; same as male except: body short, broad; face strongly convex; clypeal apex subtruncate; flagellum short, coiled; flagellomeres broader than long; leg segments robust, foretarsi with long rake spines, mid and hindtibiae and femora broad, flattened and spinose; apical metasomal tergum with broadly ovoid, longitudinally ridged pygidium; apical sternum apical margin with broadly rounded lip.

Distribution.―This genus occurs from southern Canada to central Argentina, but is unknown from Chile.

Biology.―In North America hosts and parasites have only been reported for Myzinum quinquecinctum (Fabricius) . This species attacks scarabaeid larvae in the genus Phyllophaga and is parasitized by D. quadriguttata (Say) (also given as junior synonym Dasymutilla permista Mickel in Krombein 1979) ( Mutillidae ) and Villa fulvohirta (Wied.) (Bombyliidae) ( Krombein 1979).

Discussion.―These are large, distinctive-looking wasps. There are only two genera in the subfamily Myzininae in the Americas, Myzinum and Pterombrus Smith. In both sexes Myzinum can be distinguished by the usually strongly bulging genal bridge (flat in Pterombrus ), large, subtriangular mesopleural lamellae (short and subtruncate in Pterombrus ), and black and yellow coloration (no yellow markings in Pterombrus though some may be metallic blue or purple, or partly red). Female Myzinum can be distinguished from female Pterombrus by the robust body (slender and elongate in Pterombrus ) and by the apical separation of the marginal cell from the costal margin of the forewing (not separated in Pterombrus ). Male Myzinum have the apical metasomal tergum apically divided into two long teeth or lobes (apically rounded in Pterombrus ).

There are only two other groups of wasps that Myzinum are likely to be confused with, the tiphiid genus Epomidiopteron Romand and members of the family Scoliidae . Epomidiopteron is a relatively rarely collected genus in the tiphiid subfamily Tiphiinae . Epomidiopteron are heavy-bodied wasps and both sexes superficially resemble female Myzinum . They can be immediately distinguished from Myzinum females by the lack of antennal lobes and lack of a protuberant hypostomal angle. Scoliids can be distinguished from Myzinum by the pleated wing membrane and broad, flat metasternal plate. The males of both Epomidiopteron and Scoliidae are relatively robust and lack the unciform apical metasomal sternum typical of male Myzinum .

The only revisionary studies of Myzinum were done by Krombein (1938, 1942) who largely emphasized differences in color and integumental sculpturing in females and male genitalic characteristics to distinguish species, and by Argaman (1994) who over split a group where even species level characteristics are problematic. Argaman’s genera are based on species-level diagnostic features.

Argaman divided the genus Myzinum into six genera, Cocovasna, Ekepirka, Fikoplesa, Gonordula. Keyovaska and Tokoparta based on modifications of male leg segments and sculpturing of male and female metasomal terga, scutum and propodeum. Bartalucci (2004) synonymized three of the genera under Myzinum , leaving Fikoplesa, Ekepirka and Tokoparta. As with the three genera that Bartalucci synonymized, there are no features given by Argaman to justify these remaining genera that are diagnostic for more than his nominate species.