Cirrospilus
belongs to the tribe
Cirrospilini,
having funicle 2-segmented in both sexes, propleura separated
posteriorly, submarginal vein with 3 or more setae dorsally and
2 pairs of scutellar setae.
We have considered
C. ambiguus separately, as this species
has morphological features unique within
Cirrospilus.
Indeed,
C. ambiguus may be quite easily distinguished
from all the other
Cirrospilus
by the notauli, which curve to meet the anterior margin of axilla,
rather than extending to the hind margin of mesoscutum. This character
has usually been used as one of the main features to distinguish
Cirrospilus from
Zagrammosoma
and
Diglyphus. In the description
of
C. ambiguus (
Hansson
& La Salle, 1996), the authors preferred to place this
species in
Cirrospilus
because it doesn’t have other characters usually associated
with
Zagrammosoma or
Diglyphus: it is mainly
metallic in coloration and without a vaulted vertex, while
Zagrammosoma
has vaulted vertex and is always non-metallic; some yellow markings
are present, while
Diglyphus
are always completely metallic.
C. ambiguus may be distinguished from the other
Cirrospilini
included in the key as follows:
Danuviella,
Meruana and
Semielacher
have a distinct petiole; moreover,
Meruana
has propodeal plicae which converging posteriorly;
Semielacher
has notauli reaching mesoscutum posteriorly;
Diaulinopsis
has postmarginal vein long at least 1.50 the stigmal vein length
and notauli reaching posterior margin of mesoscutum.