Fig. C3.1 (live female, habitus)
Both sexes of Sirex are recognized by presence of the fore wing vein Cu1, the dark areas of the body with dark blue or green metallic reflections, the gena without ridge behind eye, and without a white spot dorsally. Females also have the cornus in dorsal view not constricted near the middle.
Color. Black portions of body with dark blue or green metallic reflections, remaining pale surfaces, if present, light reddish brown to reddish brown.
Head. Antennal sockets with distance between their inner edges 1.5–2.0 times distance between inner edge of eye and outer edge of socket (Fig. C3.2). Distance between inner edges of lateral ocelli about as long as distance between outer edge of lateral ocellus and nearest edge of eye (Fig. C3.3). Maximum distance between outer edges of eyes clearly less than maximum width of head (thus, in frontal view, genal edge completely visible and not intersected by outer edge of eye) (Fig. C3.2). Minimum distance between inner edges of eyes about 1.5 times maximum eye height (Fig. C3.2). Gena without ridge behind eye and without white spot (at most with brown spot in males of one species) (Fig. C3.4), with large pits, each not elevated as low tooth. Head with setae sharp at apex. Antenna with 12 or more flagellomeres (the smallest specimens have the lowest number), and middle flagellomeres in dorsal view 1.5–3.0 times as long as wide; middle and apical flagellomeres with sensory pits over all except outer surface, apical 5–10 flagellomeres each with sensory oval impression on inner dorsal and inner ventral surfaces.
Thorax. Pronotum smooth or pitted over less than 0.5 of anterior surface. Mesoscutum densely pitted over median 0.5–0.7 only. Mesotarsomere 1 in lateral view not enlarged, its dorsal and ventral edges almost parallel and base of tarsomere at most 0.7 times its maximum width. Metatibia with two apical spurs, in male metatibia in lateral view 3.5–5.6 times as long as maximum width. In female, metatarsomere 2 in lateral view 1.5–5.0 times as long as maximum height. Metatarsomere 5 as long as metatarsomere 2 or metatarsomeres 2 + 3. Fore wing with apex acutely and angularly rounded, with vein 2r–m joined to cell 2M (as in Fig. B1.71), with vein 2r–m present, with cell 1Rs2 clearly wider than long, with cell 3R1 3.0-3.8 times as wide as long, with cell 2R1 about 0.5 times as wide as cell 3R1, with vein 2r-rs joining stigma near middle, with stigma gradually attenuated even distal to junction with vein 2r-rs (Fig. A3.30), with vein Cu1 almost always fully developed, with vein 1cu–a joining vein Cu about mid way between veins 1m–cu and M, with vein 2A adjacent to posterior edge of wing for 0.25 times length of cell 1A length (Fig. A3.30), and with vein 3A absent or present but short. Hind wing with anal cell 1A (as in Fig. 1.44); hamuli clearly present both basal and apical to junction of veins R1 and C (Fig. B1.11).
Abdomen. Female. Cornus in dorsal view short or long, lateral edges markedly to slightly convergent, but not constricted (Figs. B2.87 & B2.88). Tergum 9 with lateral edges of median basin slightly divergent, straight or almost so, and sharply outlined for less than 0.3 times median length of basin (Figs. B2.87 & B2.88), and with basin base (outlined by black furrows laterally) 0.85–1.5 times as wide as median length of basin. Cercus present but very small and wart-like. Sheath. Length of basal section 0.4–1.4 times as long as apical section; apical section without longitudinal lateral ridge, and with teeth in apical third of dorsal margin (as in Fig. B1.48) and each tooth usually with small seta at base. Ovipositor. Lancet with any of annuli 10–17 aligned with junction of basal and apical sections of sheath; first two or three annuli anterior to teeth annuli each with clearly outlined, open ended pit extending along most of annulus and most pits with ventral edge ridged; pits anterior to first annulus before teeth annuli large to very large and edge of annulus below pit sharply and acutely produced and clearly outlined to ventral edge of lancet (Fig. C3.5).
Sirex is diverse in the Northern Hemisphere with 28 extant species (15 known from the Palaearctic Region) (Taeger and Blank 2011, Taeger et al. 2010). This is the most diverse genus in the New World with 14 species, one of which, S. noctilio, was introduced from the Old World. The genus is widespread across North America. More species are expected from the Mexican highlands and perhaps the large Caribbean islands. We studied six Palaearctic species in addition to the Nearctic ones.
References provided here mostly emphasize the taxonomic literature. Slippers and Haugen (2009) maintain an extensive bibliography (about 430 papers) on all aspect of Sirex, and their links to other information.
The 14 species treated are: