PIPIZA Key 1.a. Head in side view: implantation of Introduction antennae on upper 1/2 of head (figure 575); abdomen: more elongated, with Pipiza are medium-sized, blackish hover- no, 2 or 4 spots. Males: eyes: angle of flies with a broad abdomen. They are approximation 85° or more. Females: mostly encountered on the forest edge. P. frons with dust spots › 2 quadrimaculata seems to prefer shady con- 1.b. Head in side view: implantation of ditions, but other Pipiza regularly bask in antennae midway on the head (figure the sun. Their larvae are predators of gall- 576); abdomen: rounded with 4 yellow forming aphids. P. luteitarsis is found in spots which may be obscured (figure galls of Schizoneura ulmi, an aphid that 577). Male: eyes: angle of approximation forms galls on Ulmus. P. festiva is found on 80° or less. Female: frons without dust galls of the aphid Pemphigus spyrothecae on spots. 5-8 mm. Northern and Central Populus. These aphids have ‘soldiers’, spe- Europe, Siberia › Pipiza quadrimacula- cialised aphid larvae that protect the ta Panzer entrance of the gall. Pipiza seems to over- Jizz: abdomen broadly oval, with 4 spots; flying in come this barrier (Schmid, 1996). forests in shady places near running water. 2.a. Tars 1: completely yellow, rarely Recognition metatars somewhat blackened above, tars 2 and 3 largely yellow with some Pipiza contains two sets of species. The darkened segments › 3 first set can be separated with confidence 2.b. Tars 1: at least segment 5 black, often and contains P. accola, P. quadrimaculata, P. segment 3-5 or all segments black, tars 2 luteitarsus, P. festiva, P. fasciata, P. austriaca and 3 largely or entirely black › 6 and P. lugubris. The second set contains species whose specific status is subject to 3.a. Femur 3: not thickened, without cav- doubt; it contains P. fenestrata, P. signata, P. ity below (figure 579); face in front bimaculata, P. noctiluca and P. notata. There view: broadened towards mouth edge are no satisfactory characters for P.signata with eye margins divergent; wing hya- and P. notata, therefore these species are line or diffusely infuscated › 4 omitted from the key. The key is based on 3.b. Femur 3: thickened, with a cavity Wolff (1998), an unpublished key of A. below where the tibia fits (figure 578); Barendregt, a translation of Violovitsh’s face in front view: not broadened key and information on P. bimaculata, P. towards mouth edge with eye margins noctiluca, P. signata and P.fenestrata by Th. parallel; wing: with dark spot; › 5 Zeegers. D. Wolff kindly provided a pair of P. accola for comparison. figure 575. Pipiza lugubris, head of male figure 576. Pipiza quadrimaculata, head of (Verlinden). male (Verlinden). 165 figure 580. Pipiza festiva, abdomen and ter- gite 3 of female (Verlinden). 581. 582. figure 577. Pipiza quadrimaculata, habitus of female (Verlinden). figure 581. Pipiza lugubris, femur 3. figure 582. Pipiza austriaca, femur 3 (Verlinden). 4.b. Head in front view: face at antennal implant wider than the width of an eye 578. at that height (figure 586, figure 587). Male: frons inflated and angle of approx- imation of eyes 100-110°. Female: ter- gite 5 twice as wide as long; frons: dust spots larger, each about 1/4th of the width of the frons. 7-9 mm. Central Europe, Siberia › Pipiza accola 579. Violovitsh Jizz: a greyish Pipiza, covered with long, pale hairs. figure 578. Pipiza festiva, femur 3. 5.a. Tergite 2 with large yellow spots, figure 579. Pipiza luteitarsis, femur 3 often broadly connected; tergite 3 black (Verlinden). (figure 580). Males: eyes with white hairs. Female: antennae: 3rd segment 1.2 times as long as wide. 9-10 mm. Central 4.a. Head in front view: width of face at and Southern Europe, in Asia to Pacific antennal implant about equal to the coast › Pipiza festiva Meigen width of an eye at that height. Male: Jizz: hairs on abdomen ochre-yellow. angle of approximation of eyes about 5.b. Tergites 2 and 3 with large brown 90°. Female: tergite 5 as wide as long; spots or bands. Males: eyes with dark frons: dust spots small, each at most 1/6th hairs. Female: antennae: 3rd segment 1.5 of the width of the frons. 7-9 mm. times as long as wide. 9-10 mm. Central Northern Europe, south to Northern and Southern Europe › Pipiza fasciata France › Pipiza luteitarsis Zetterstedt Meigen 166.