Myzinum confluens (Cresson)

Kimsey, Lynn S., 2009, Taxonomic purgatory: Sorting out the wasp genus Myzinum Latreille in North America (Hymenoptera, Tiphiidae, Myzininae), Zootaxa 2224, pp. 30-50 : 41

Myzinum confluens (Cresson)

Fig. 15

Myzine confluens Cresson 1865:443 . Holotype female; “Colorado Territory” (PHILADELPHIA).

Male.―Body length 11–19 mm. Head: frons punctures contiguous to 1 PD apart near midocellus; interocellar distance equal to ocellocular distance; hypostomal angle forming 90° angle; flagellomere I 1.2–1.4x as long as broad; flagellomere XI length 2.3x breadth. Thorax: pronotal punctures 3–4 PD apart; mesopleuron with omaulus; fore and hindcoxae and midtrochanter unmodified. Metasoma: tergum VII dorsally flattened and smooth, sparsely punctate. Genital capsule ( Fig. 15 ): paramere without dorsal lobe, broadly rounded, with marginal setae more than half as long as volsella, ventral lobe 3– 4 x as long as broad, spines along apical half of lobe; volsella flattened, subtriangular, apically setose, subequal in length to paramere ventral lobe; aedeagus apical bulb slender, 1.5x as broad as shaft below. Color: black, with yellow markings; clypeus yellow, inner eye margin with yellow band, antennal lobe with yellow spot, mandible basally yellow, scape ventrally yellow; pedicel and flagellum reddish ventrally becoming darker dorsally; pronotum with transverse yellow band along posterior and anterior margins, anterior band often broken medially; scutum, scutellum and metanotum with medial yellow spot; mesopleuron with large anterior and smaller posterior yellow spot; propodeum with small sublateral spot; coxae with yellow mark; femora brown basally, yellow apically; tibiae and tarsi yellow; metasomal terga I–VI with transverse posterior yellow band, sterna II–VI with posterolateral yellow spot; wing membrane untinted, veins yellow to pale brown. Ve st it ur e: silvery.

Female.―Body length 10–13 mm. Head: hypostome forming right angle in profile; vertex punctures 1–3 PD apart; ocellocular distance 1.7–1.8x interocellar distance; flagellomere I length 0.7x breadth; clypeal apex evenly rounded; flagellomere I 1.5x as broad as long. Thorax: pronotum without small interpunctures, punctures sometimes confluent; propodeum finely cross-ridged laterally, smooth posteriorly; forebasitarsis with five rake spines. Color: black, with yellow markings; face yellow, with black mark extending down vertex, with a large lobe extending to above antennal socket on either side of midocellus, with continuous to broken yellow band across back of head from mandibular socket to socket, scape and mandible yellowish to red; pronotum with broad transverse yellow band on anterior and posterior margins; mesopleuron, tegula and propodeum mostly yellow; scutum and scutellum medially and laterally yellow; metanotum yellow medially; legs largely yellow; metasomal terga I–V and sterna II–V yellow, with narrow, transverse medial brown band to having discrete anterior and posterior transverse yellow bands, segment VI brown; wing veins red, membrane untinted to lightly brown-tinted. Vestiture: silvery.

Distribution.― USA: Arizona: Cochise, Santa Cruz Counties; Colorado: Adams Co.; New Mexico: Hidalgo Co.; MEXICO: Chihuahua, Sonora, Sinaloa; 9 males and 17 females were studied.

Discussion.―The most distinctive feature of this species is in the male genitalia. The volsella is subtriangular in cross-section and about as long as the ventral lobe of the paramere. The only other North American Myzinum species with such a large volsella is maculatum . However, in confluens the volsella is flat in cross-section, whereas it is subtriangular in cross-section in maculatum . The most distinctive feature of female confluens is the double banded terga, which have a complete transverse band along both the anterior and posterior margins. Other diagnostic features of the females include the ocellocular distance, which is 1.8x the ocellocular distance, flagellomere I is 0.7x as long as broad, and the forebasitarsis with five rake spines. It has not been possible to confirm the sex association in this species, so Krombein (1938) is being followed. It may very well be that the female coloration is a color variant and that the male volsellar shape is also a variant of the condition seen in maculatum .

Figures

FIGURES 13 – 22. Male genital capsule, lateral view. Abbreviations: ae = aedeagus, dl = paramere dorsal lobe pa = paramere, v = volsella; vl = paramere ventral lobe.