Chaetolonchaea

Key to World species of Chaetolonchaea

(Revised after McAlpine 1982)

1. Entire body dulled by silver-grey pollinosity, eye hairs short or much shorter than width of parafacial...................2

- Body mainly subshining black, eye hairs long to short.........................................................3

2. Pre-scutellar area (between base of scutellum and transverse row of strong scutal setae) with 1–3 setulae, antennal flagellomere 2x as long as wide, male frons silvery pruinose (NE China)..................................... C. pruinosa Morge

- Pre-scutellar area bare, antennal flagellomere 1.25–1.4x as long as wide, male frons dull greyish pruinose (NE China)............................................................................................. C. pellicula Morge

3. Orbital plate, in addition to orbital seta, with one or more setulae, eye hairs longer than the width of parafacial in both sexes, katepisternum usually with 3 strong setae, hind femur usually with 4–5 outstanding anteroventral setae. Male terminalia: Surstylus with usually only 1 strong prensiseta. Large, coarsely bristled, densely long setulose species (Europe)................................................................................................... C. dasyops (Meigen)

- Orbital plate bare, eye hairs shorter than the width of parafacial at least in females, usually with 2 katepisternal setae, hind femur with 1–2 anteroventral setae. Male terminalia: Surstylus with 2–3 prensisetae. Smaller species with sparser and shorter setulae..............................................................................................4

4. Eye hairs long, in male about as long as width of parafacial, in female distinctly longer than width of an ommatidium, easily seen................................................................................................5

- Eye hairs short, in male much shorter than width of parafacial, in female not or scarcely longer than width of an ommatidium, sparse and scarcely discernable...........................................................................6

5. Facial carina narrow, between bases of antennae about 0.3x as wide as narrowest part of parafacial (in females wider). Gena, at narrowest point about 0.2x as wide as height of eye. Male terminalia: in posterior view apex of cerci forming two lobes with a U-shaped incision between (Russian far-east)................................................. C. gracilis Czerny

- Facial carina broader, between bases of antennae about 0.6x as wide as narrowest part of parafacial. Gena, at narrowest point about 0.3x as wide as height of eye. Male terminalia: in posterior view with apex of cerci bluntly pointed. (N. America)...................................................................................... C. americana McAlpine

6. Frontal carina broad, at narrowest point between bases of antennae fully 0.6x as wide as parafacial, prescutellar area with approximately 6–7 setulae, wing membrane orange-yellow especially at base (Europe)............... C. brevipilosa Czerny

- Frontal carina narrow, at narrowest point between bases of antennae scarcely 0.3x as wide as parafacial, prescutellar area with approximately 2–4 setulae, wing membrane creamy yellow....................................................7

7. Black setulae of vein C extending to a point about 1/3 of distance between apices of vein R2+3 and vein R4+5; distance between apices of vein Sc and vein R1 longer than greatest width of costal cell. Male terminalia: in posterior view apex of cerci bluntly pointed (Fig. 18) (Europe).......................................................... C. pallipennis (Zetterstedt)

- Black setulae of vein C extending to end of vein R4+5; distance between apices of vein Sc and vein R1 shorter than greatest width of costal cell. Pre-scutellar area with 1–3 setulae, antennal flagellomere 1.6x as long as wide. Male terminalia: in posterior view apex of cerci forming two rounded lobes with a V-shaped incision between (Fig. 14) (N. China)................................................................................................. C. alliumi Zhang et Xue