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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
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Key to Sirex - Males
1. A) Metafemur black (Fig. B2.89).  
a) Metafemur mainly reddish brown (Figs. B2.90-B2.92).  
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2(1). A) Legs completely black (including base of metatibia) (Fig. B2.93).  
  [Additional characters. Head with dorsal surface coarsely pitted, but pits scattered.]
a) Fore and middle legs with tibiae and tarsi reddish brown or paler (mesotibia and/or mesotarsomere 1 partly brown or black on dorsal surface in some species) (Figs. B2.94 & B2.95).  
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3(2). A) Head with dorsal surface finely pitted and the pits scattered (Fig. B2.96).  
a) Head with dorsal surface coarsely and densely pitted (Fig. B2.97).  
  [Additional characters. Abdomen black except for segments 5 and 6 (rarely an additional segment), or abdomen light reddish brown except for anterior segments.]
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4(3). A) Metatibia with extreme base light reddish brown (Fig. B2.98).  
B) Mesotibia and/or mesotarsomere 1 with dorsal surface light reddish brown and with brown or black spot dorsally (spot size varies from small to large) (Fig. B2.100).
    [Notes. Many specimens of this color form seen from Alaska, northernmost British Columbia, and the Yukon Territory, and Saskatchewan east to Newfoundland. In a few of these specimens, abdomen completely black. In Alaska, femora commonly black, and mesotibia and mesotarsomeres 1–3 widely black.]  
a) Metatibia with base more widely light reddish brown (Fig. B2.99).  
b) Mesotibia and mesotarsus completely light reddish brown (Fig. B2.101).
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5(1). A) Metafemur completely reddish brown; metatibia light reddish brown or black (Figs. B2.102 & B2.103).  
B) Gena black with dark blue metallic reflections (Fig. B2.105).
a) Metafemur reddish brown and black along dorsal surface; metatibia brown (Fig. B2.104).  
b) Gena brown posterodorsally (Fig. B2.106).
  [Additional characters. Metatibia and metatarsus brown, not reddish brown or black; dorsal surface of head coarsely and densely pitted.]
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6(5). A) Metatibia and metatarsus reddish brown or paler, and base of metatibia not obviously pale (Fig. B2.107).  
B) Gena posterodorsally with pits mostly touching (except S. californicus) one another to about one diameter apart, only a few pits farther apart (Fig. B2.110).
a) Metatibia and at least metatarsomeres 1-3 almost completely black, and metatibia clearly light reddish brown at base or black (Figs. B2.108 & B2.109).  
b) Gena posterodorsally with pits mostly 1–3 diameters apart, the pits rarely touching (Fig. B2.111).
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7(6). A) Antenna black or, at most, pedicel and flagellomeres 1 and 2 brown (Fig. B2.112).  
B) Fore wing clearly yellow tinted, especially the cells posterior to costal cell and stigma (Fig. B2.114).
  [Additional character. Head densely pitted dorsally.]
a) Antenna with at least scape, pedicel and flagellomeres 1-5 light reddish brown (Fig. B2.113).  
b) Fore wing clear, scarcely tinted (Fig. B2.115).
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8(7). A) Antenna with scape, pedicel and flagellomeres 1-3 or 4 light reddish brown, remaining flagellomeres black (Fig. B2.116).  
B) Head dorsally with scattered pits and pit diameter 0.15-0.3 times lateral ocellus diameter (Fig. B2.118).
a) Antenna almost completely reddish brown or paler (apical 2–4 flagellomeres darker in a few specimens) (Fig. B2.117).  
b) Head dorsally densely pitted and pit diameter 0.3–0.4 times lateral ocellus diameter (Fig. B2.119).
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9(8). A) Coxae black (as in Fig. B2.120).  
B) Mesoscutum submedially with net-like arrangement of polygonal pits with distinct raised margins; pit diameter 0.5–1.0 times lateral ocellus diameter (Fig. B2.122).
a) Coxae completely reddish brown (Fig. B2.121).  
b) Mesoscutum submedially with mostly round pits usually separated from one another, and usually without raised margins; pit diameter 0.3–0.7 times lateral ocellus diameter (Fig. B2.123).
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10(6). A) Metatibia at base widely light reddish brown (Fig. B2.124).  
B) Head with setae posterodorsally behind eye each with a small pit at their base or without pit (Fig. B2.127).
C) Mesoscutum submedially with small pits, each usually with a tooth behind (giving a rasp-like pattern), the tooth usually not fused laterally with others (Fig. B2.129).
a) Metatibia at base narrowly light reddish brown (Figs. B2.125 & B2.126).  
b) Head with setae posterodorsally behind eye each with a deeply outlined pit at their base (Fig. B2.128).
c) Mesoscutum submedially with moderate to large pits, each often surrounded with raised margins forming a net-like pattern (Fig. B2.130).
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11(10). A) Mesotibia and/or mesotarsomere 1 with brown to black spot on dorsal surface (Fig. B2.131).  
a) Mesotibia and metatarsomere 1 completely light reddish brown (Fig. B2.132).  
    [Note. In the range of Balsam fir in Alberta and perhaps Saskatchewan, males of S. cyaneus matching above two couplets cannot be segregated with certainty using this character. Elsewhere this character almost always (99%) works.]  
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12(11). A) Abdomen with tergum 8 (in most specimens) and sterna 8 and 9 (in all specimens) black or mainly so (Fig. B2.133).  
B) Western Alberta and eastward.
    [Note. In western Alberta the apex of abdomen is light reddish brown. Character works from Manitoba eastward. No males seen from Saskatchewan.]  
a) Abdomen with apical segments light reddish brown (Fig. B2.134).  
b) Rocky Mountains and westward.
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13(12). A) Mesotibia dark brown on about 0.5 of outer surface and dark spot not expanded on inner and lateral surfaces; mesotarsomere 1 or 1 and 2 dark brown (Fig. B2.135).  
B) Metatibia with base narrowly light reddish brown, the length of reddish brown area about as long as minimum width of tibia (Fig. B2.137).
C) Abdomen with tergum 7 and sterna 7 and 8 black (Fig. B2.139) or light reddish brown (Fig. B2.140) (if the latter, use A, B, and D).
D) Across North America where spruces grow.
    [Note. Specimens with abdomen light reddish brown apical segments rarely seen in eastern North America, but commonly seen in western North America. In Alaska and probably Yukon, mesotibia very darkly and widely black as in S. varipes. Sirex varipes recorded only south of southern British Columbia.]  
a) Mesotibia black on about 0.7 of outer surface, and partly or completely covering lateral and inner surfaces; tarsomeres 1 and 2 or 1–3 black (Fig. B2.136).  
b) Metatibia with base very narrowly light reddish brown, the length of reddish brown area shorter than minimum width of tibia (Fig. B2.138).
c) Abdomen with apical segments light reddish brown (as in Figs. B2.140 & Fig. B2.141).
d) Rocky Mountains westward.