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Siricidae (Hymenoptera: Symphyta: Siricoidea) of the Western Hemisphere
CJAI 21, July, 2012
doi: 10.3752/cjai.2012.21
Nathan M. Schiff, Henri Goulet, David R. Smith, Caroline Boudreault, A. Dan Wilson, and Brian E. Scheffler

Urocerus taxodii (Ashmead)

Fig. C27.1, Schiff et al. 2006: 78, 79 (female habitus)
Fig. C27.2, Schiff et al. 2006: 77 (male habitus)
Fig. C26.3 (map)

Sirex taxodii Ashmead, 1904: 63. Lectotype female (USNM), here designated and examined by DRS, and labeled “1611b Hopk. U.S.”, “Fiske Colr., Brunswick, GA.”, “Taxodium distichum”, “female Type No. 7681, U.S.N.M.”, “Sirex taxodii Ashm [handwritten]”. Paralectotypes: 1 female and 1 male. All three types are from “Brunswick, Ga.”, not Tryon, N.C. as mistakenly stated by Ashmead. The rest of the label data was correctly given by Ashmead: “No. 1611; bred by Mr. W. F. Fiske from the Cypress (Taxodium distichum, L).”. We have no specimens of U. taxodii from Tryon, though other species mentioned in Ashmead’s paper are from Tryon, N.C. Type locality: Brunswick, Ga.
Urocerus taxodii; Bradley, 1913: 17, 20 (change in combination); accepted by Burks 1958: 17; Smith 1979: 129.

Diagnostic Combination

Among adults of U. taxodii with the basal 0.3–0.7 of the flagellum black and sharply separated from the white apical section [cressoni], females are recognized by the black abdominal segments 1–9 and a light reddish brown cornus, and males by the metatibia with white in basal 0.25, and reddish brown pro- and mesotibia and pro- and mesotarsus.



Color. Head black except for white spot behind eye. Maxillary palp and mandible black. Scape, pedicel, and flagellum (basal 0.3–0.6) black; flagellum white in apical 0.4–0.7, and apex of last flagellomere clearly darkened. Thorax black. Legs black but white basal 0.25 of metatibia and metatarsomere 1. Fore and hind wings very darkly tinted. Abdomen black, but light reddish brown in apical 0.7 of cornus (Fig. B4.24).

Head. Vertex densely pitted median to the white genal spots.

Thorax. Metatarsomere 2 in lateral view about 3.0 times as long as high (Fig. B4.28), and with tarsal pad about 0.7 as long as ventral length of tarsomere (Fig. C27.3).

Abdomen. Median basin of tergum 9 with base (outlined by two lateral black longitudinal furrows) 2.0 times as wide as median length, with maximum width about 2.2 times as wide as median length, and with median length about 0.25 times cornus length. Cornus in dorsal view constricted near base, and minimum width of constriction 0.6–0.9 times maximum width subapically. Tergum 8 with microsculpture of sublateral surface (between spiracle and pitted sculpticells on central area) with meshes, and sculpticells raised and scale-like (thus, surface matt); tergum 9 with dorsal surface lateral to median basin with meshes and scale-like sculpticells, smooth and without meshes near anterior portion of median basin (Fig. B4.26), and ventral surface with meshes and scale-like and slightly elevated sculpticells. Sheath. Length 0.87–1.0 time length of fore wing, apical section 1.25–2.0 times as long as basal section. Ovipositor. Lancet with 24–29 annuli (annuli in basal 0.5 of lancet outlined but difficult to see); junction of basal and apical section of sheath aligned between 4th and 5th annuli; apical part of lancet with 9–10 pits. Pits 0.05–0.1 times as long as an annulus, becoming gradually small, and disappearing in basal 0.4 of apical sheath section. Edge of last 6–8 annuli before teeth annuli extending as ridge to ventral margin of lancet.


Color. Head black except for white genal spot extending from level of lower eye margin to top of eye, and light reddish brown in ventral third (Fig. B4.48). Flagellum black in basal 0.3–0.6 and white in apical 0.4–0.7, and apex of last flagellomere clearly darkened. Thorax mainly black but reddish brown over most of dorsal surface of pronotum (Fig. B4.48), mesoscutellum and metanotum. Legs black but reddish brown on pro- and mesotibia, pro- and mesotarsus, and metatarsomeres 3–5; light reddish brown basal 0.25 of metatibia and metatarsomere 1 (Fig. B4.46 hind leg). Fore and hind wings darkly tinted. Abdomen light reddish brown.

Head. Vertex densely pitted median to the white genal spots.

Thorax. Metatibia 4.7 times as long as maximum width. Metatarsomere 1 in lateral view 5.6 as long as maximum height (Fig. B4.46).

Host and Phenology

Based on published records and 2 reared and confirmed specimens studied, Urocerus taxodii has been reared from Taxodium distichum, (Cupressaceae) (Bradley 1913, Cameron 1965, Smith, 1979: 129). The Ontario and Virginia specimens suggest that Juniperus virginiana, the only unusual Cupressaceae in the area, might also be a host.

Based on 7 field-collected specimens, the earliest and latest capture dates are from late May to late September.


CANADA: ON. USA: DC, FL, GA, MO, MT (mislabeled or associated with lumber from southeastern United States), NY (Rohwer 1928), VA. Urocerus taxodii is basically in southeastern United States, but the Ontario and Virginia records suggest an eastern North American range (Fig. C26.3).

Specimens studied and included for the distribution map: 12 females and 1 male from CNC, FSCA, and USNM.

Specimens for molecular studies: 5 specimens. See Fig. E2.4a.

USA. Mississippi: 2006, CBHR 31, 658; 2003, CBHR 141, 658; 2002, CBHR 142, 658; 2002, CBHR 143, 658; 2002, CBHR 144, 658.