Among females with completely black legs and abdomen, and a clear fore wing [mexicanus], those of S. xerophilus are recognized by the coarse and crater-like pits over most of the median half of the mesoscutum. Among males with a reddish brown hind leg beyond the coxa [californicus and obesus], those of S. xerophilus are recognized by the completely reddish brown antenna and black coxae.
Color. Body, legs, palps, and antenna black with dark blue metallic reflections. Fore wing lightly tinted (Fig. B.2.32).
Head. Gena with pits (except centrally) 0.0–1.5 pit diameters apart; vertex and postocellar area with pits 0.0–1.0 pit diameters apart; and each pit diameter about 0.2–0.45 that of lateral ocellus.
Thorax. Mesoscutum widely covered with net-like pits in median area (Fig. B2.45). Metatarsomere 2 in lateral view 2.2–2.6 times as long as high, and its length about 1.2 times length tarsomeres 3 + 4; tarsal pad 0.3–0.5 times as long as ventral length of tarsomere. Fore wing vein 3A absent (Fig. B2.47).
Abdomen. Median basin of tergum 9 with basal width 1.0–1.3 times as long as median length, maximum width 1.2–1.6 times as long as median length, and median length about 0.7 times as long as cornus length. Cornus in dorsal view short, with edges angularly rounded or very angular midway, its median length 0.9–1.2 as long as maximum width of abdomen at junction of terga 9 and 10. Sheath. Length 0.7–0.9 times fore wing length, basal section 1.1–1.2 times as long as length of apical section. Ovipositor. Lancet with 33–36 annuli (basal annuli clearly outlined); junction of basal and apical section of sheath aligned between 11th and 12th to 13th and 14th annuli, with 29–32 pits beginning with annulus 2; pit of annulus 2 only extending to edge of annulus 1 (Fig. B2.51, base). Pits near middle annuli (Fig. B2.51) or area at base of apical section of sheath 0.7–0.8 times as long as an annulus, and about 0.6 times as high as lancet height in lateral view, with posterior edge hardly outlined, and 2.5–3.4 times as long as high (Fig. B2.51, middle); annulus length/ovipositor diameter (lance + lancet) for annulus 2 is 1.9–2.35, for annulus 5 1.5–2.00, for annulus 10 1.4–1.7, and for annulus 13 1.40–1.60 (7 specimens). Last 4-5 annuli before teeth annuli as well as first tooth annulus with ridge on ventral edge of pit. Edge of apical 4-5 annuli before teeth annuli extending as ridge to ventral edge of lancet.
Color. Head, palps, thorax, and abdominal segments 1 or 1 and 2 black with dark blue metallic reflections; remaining abdominal segments and antenna (a little darker apically) light reddish brown. Coxae black, remaining of articles of legs reddish brown. Fore wing clear.
Thorax. Metatibia 4.0 times as long as maximum width. Metatarsomere 1 in lateral view 3.3 times as long as maximum height.
Holotype female (USNM) in perfect condition; labeled [White with red frame] [White] “Panguitch Utah” “Hopk. U.S. 4533j” “H. E. Burke Collector” “Pinus ponderosa” “HOLOTYPE Sirex xerophilus N.M. Schiff, 2011”. Type locality: Panguitch, Garfield Co., UT.
Paratypes. 11 females and 1 male. MEXICO. Chihuahua: Intercepted at El Paso, Texas (#51422), 28.IX.1948, pine lumber (#48–16199) (2F, USNM); [no locality] madera [lumber] pine, J. A. Backer (2F, USNM). USA. Colorado: Larimer Co., Big Elk Fire, 40°17'02"N 105°22'59"W, 16.IX.2005, S. M. McElway (5F, CNC). Utah: Garfield Co., Panguitch, Hopk. U.S. 4533j, H. E. Burke, Pinus ponderosa (1F, 1M, USNM).
The name xerophilus is an adjective derived from two Greek words meaning “dry loving” because the species is found in dry ecosystems where its only recorded host, Pinus ponderosa, occurs.
Specimens of S. xerophilus have been reared from Pinus ponderosa in Utah. They were also collected on pine lumber in Mexico.
One specimen was captured on September 16, three on September 17, two on September 28 and two on November 26.
MEXICO: (northern region). USA: CO, UT. Sirex xerophilus is known from southern Utah and northern Colorado south to northern Mexico (Fig. C9.6).
Specimens studied and included for the distribution map: 11 females and 1 male from CNC and USNM.
Specimens for molecular studies: 5 specimens. See Fig. E2.5b.
USA. Colorado: 2005, CBHR 538, 658; 2005, CBHR 541, 658; 2005, CBHR 542, 658; 2005, CBHR 544, 658; 2005, CBHR 545, 658.