Dasysyrphus Have Yellow on Black, Oval Bodies
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Recognition 263. Dasysyrphus have yellow on black, oval bodies. They are similar to many Syrphini genera, in particular Eupeodes and Parasyrphus, but their eyes are haired (Eupeodes and most Parasyrphus have bare eyes) and the abdomen is spotted rather than banded (except for D. tricinctus and D. eggeri). The key is based on Van der Goot (1981), Verlinden (1991), Bradescu (1991), Doczkal (1996) ,Reemer (2002) 264. and Bartsch et al. (2009a). As Speight (2003) points out, D. pauxillus, D. pinastri, D. lenensis and D. nigricornis are not well- figure 263. Criorhina floccosa, tibia 1. defined at the moment. D. postclaviger and figure 264. Criorhina berberina, tibia 1 D. nigricornis are added after the interpre- (Verlinden). tation of Bartsch et al. (2009a). Key 1.a. Tergites 3 and 4 with equally-sized yellow patterns; tergite 2: pale pattern always present, equally broad or broader than pattern on tergites 3 and 4 › 2 1.b. Tergite 3 with yellow pattern much broader than on tergite 4; yellow pattern on tergite 2 small or absent (figure 266). 10-12 mm. Northern and Central Europe, east to Japan › Dasysyrphus tricinctus Fallén Jizz: broad, blackish species with small yellow bands on the abdomen, in flight quite similar to flying Chrysotoxum bicinctum. figure 265. Criorhina berberina, habitus of male (Verlinden). DASYSYRPHUS Introduction terg.3 Dasysyrphus dwell in forests, along forest broad edges and probably also occur high in spots trees. They visit all kind of flowers with shallow nectaries. Many species are shade tolerant and can be found inside the for- est. Males hover under tree cover. Females wander through the forest, sometimes deep in the vegetation. Their larvae prey figure 266. Dasysyrphus tricinctus, habitus of on aphids. male (Verlinden). 88 268. spot follows front dust margin stripes 269. oblique spot narrowed medianly figure 267. Dasysyrphus albostriatus, habitus of male (Verlinden). 2.a. Thoracic dorsum with 2 or 4 longi- tudinal stripes of white dust, tergites with spots (which may broadly connect) at a distinct angle to the front margin figure 268. Dasysyrphus hilaris, abdomen of (figure 267) › 3 female. 2.b. Thoracic dorsum without stripes of figure 269. Dasysyrphus friulensis, abdomen white dust; tergites with well separated of female (Verlinden). spots parallel to the front margin (or at most at a small angle) › 4 5.b. Tergites 3 and 4: spots hardly nar- rowed, at most to 0.6 times their largest 3.a. Thoracic dorsum with 2 stripes of width (figure 268); antennae pale › 7 white dust on the front 1/2 of the dor- sum; tergites with linear spots, usually 6.a. Antennae pale; scutellum: hind margin separated, but they may connect on ter- black, scutellar dorsum predominantly gites 3 and 4. 8-10 mm. Europe to Japan yellow haired; face with pale hairs. 7-11 › Dasysyrphus albostriatus Fallén mm. Northern, Central and Southeastern Jizz: oblique yellow spots on abdomen, 2 white Europe.› Dasysyrphus postclaviger Stys stripes on thorax and black pterostigma. and Moucha 3.b. Thoracic dorsum with 4 stripes of 6.b. Antennae brown to black; scutellum: white dust over the full length of the hind margin yellow, scutellar dorsum dorsum, the inner 2 most densely predominantly black haired; face pre- marked; tergites with oval spots that dominantly with black hairs. 10-12mm. broadly connect on tergites 3 and 4. 8- Northern, Central and Southeastern 10 mm. Eastern part of Central Europe, Europe. › Dasysyrphus friuliensis Van Pyrenees, east to Mongolia › der Goot. Dasysyrphus eggeri Schiner Jizz: broad yellow spots or bands on abdomen, 4 7.a. Face with black longitudinal stripe white stripes on thorax. (figure 270). Female: sternite 2 black at hind margin; frons: dust spots faintly 4.a. Tergites 3 and 4: lateral margin black marked. 8-10 mm. Northern and and yellow: yellow spots reach the mar- Central Europe, Nearctic › gin; antennae pale or dark › 5 Dasysyrphus venustus Meigen 4.b. Tergites 3 and 4: lateral margin black, Note: Bartsch et al. (2009a) remarks that D. venus- the yellow spots do not reach it; anten- tus north of the polar circle can be quite dark and nae always dark, at most 3rd segment small, resembling D. pauxillus and D. nigricornis. turning pale below › 8 7.b. Face yellow, at most mouth edge and facial knob darkened (figure 271). 5.a. Tergites 3 and 4: spots strongly nar- Female: sternite 2 pale; frons: sharply rowed to less than 0.5 times their largest marked dust spots. 10-12 mm. Northern width (figure 269); antennae pale, dark- and Central Europe › Dasysyrphus brown or black › 6 hilaris Zettersted Note: D. venustus and D. hilaris may be found to hide a species complex in the future. 89.