1. Vein 2-1A of forewing completely developed,
resulting in a closed first subdiscal cell (A); vein 1-SR+M of
forewing absent or, when present, largely unsclerotised (A); apical
half of metasoma of female largely depressed (B); body black; face
strongly narrowed in females, ventrally narrower than high (C)
(subgenus Chaenusa Haliday, 1839) ...2
- Vein 2-1A of forewing largely absent, resulting in
an open first subdiscal cell (a); vein 1-SR+M of forewing
sclerotised, complete (a); apical half of metasoma of female
strongly compressed; body largely reddish-brown; female face
slightly wider than high (subgenus Chorebidea Viereck,
1914)...
Chaenusa testacea
2. Frons (fr) and face polished (A); face and
eyes (ep) sparsely pubescent (A); each scutellar fovea (sf) with 2
or 3 longitudinal septa (A); first tergite (1t) longer than
posteriorly wide, laterally strigous, medially rugulose (B); vein
1-SR+M of forewing pigmented, but largely unsclerotised (C); distal
end of pterostigma (pt) comparatively elongate (C) ...Chaenusa
seminervata
- Frons (fr) and face granulate (a); face and eyes (ep)
densely pubescent (a); each scutellar fovea (sf) with no obvious
longitudinal septa (a); first tergite (1t) as long as posteriorly
wide, overall rugulose without longitudinal strigae (b); vein 1-SR+M
of forewing absent (c); distal end of pterostigma (pt) comparatively
shorter and more robust (c)...
Chaenusa anervata
