Key to World species
of Chaetolonchaea
(After McAlpine 1982)
1. Entire body dulled by silver-grey pollinosity, eye hairs relatively short …….2
-- Body mainly subshining black, eye hairs long to short ….. 3
2. Prescutellar area (between base of scutellum and transverse row of strong scutal setae) with 1-3 setulae, antennal flagellomere approx. twice as long as wide, male frons silvery pruinose (NE China) ... pruinosa Morge
-- Prescutellar area bare, antennal flagellomere 1.25 – 1.4 times as long as wide, male frons dull greyish pruinose (NE China) ... pellicula Morge
3. Orbital plate with one or more setulae, eye hairs very long in both sexes, katepisternum usually with 3 strong setae, hind femur usually with 4-5 outstanding anteroventral setae, large, coarsely bristled, densely long setulose species (Europe) …….. dasyops (Meigen)
-- Orbital plate bare, eye hairs short at least in females, usually with 2 katepisternal setae, hind femur with 1-2
anteroventral setae, usually smaller body with sparser and shorter setulae ... 4
4. Eye hairs ong, in male about as long as the width of the parafacial, in female
distinctly longer than the width of an ommatidium, easily seen …….. 5
-- Eye hairs short, in male much shorter than the width of the parafacial, in female not or scarcely longer than the width of an ommatidium, sparse and scarcely discernable .. 6
5. Wing narrow, scarcely 1/3 as wide as it is long, wing membrane and fringes of
calypteres brownish-yellow, abdomen relatively slender (Russian far east) ……. gracilis Czerny
-- Wing broad, distinctly more than 1/3 as wide
as long, wing membrane and fringes of calypteres pale yellow (N. America) ….. americana
McAlpine
6. Frontal carina unusually broad, at narrowest point between bases of antennae fully 2/3
as wide as parafacial, prescutellar area with approx. 6-7 setulae, wing
membrane orange-yellow especially at base (Europe) ……. brevipilosa Czerny
-- Frontal carina narrow at narrowest point between bases of antennae scarcely 1/3 as wide as parafacial, prescutellar area
with approx. 2-4 setulae, wing membrane creamy yellow (Europe) .... pallipennis (Zetterstedt)