Proacrias belongs to the subfamily
Entedoninae by having 2 setae on
submarginal vein, scutellum with a pair of setae, fronto-facial
suture distinctly separated from anterior ocellus and male scape
with sensory pores placed at the ventral edge.
Important characters to recognise
Proacrias can be the
combination of the propodeum with 2 median carinae broadly diverging
in posterior half of propodeum, the postmarginal vein slightly
longer than stigmal vein and the distinct petiole. These characters
may be used to separate particularly
Proacrias from
Achrysocharoides,
Neochrysocharis,
Chrysocharis,
Asecodes,
Trisecodes and
Closterocerus.
Proacrias usually has a distinct pronotal carina: among
Entedoninae with pronotum carinate
Apleurotropis and
Pleurotroppopsis
may be distinguished from
Proacrias by having mesoscutum
with median longitudinal groove placed posteriorly and a single
propodeal median carina,
Zaommomentedon Girault by having
mesoscutum and scutellum with complete and distinct median groove,
Platocharis Kerrich by having diverging submedian carinae
or plicae and transverse carina between submedian carina and plica,
Kratoysma Boucek by having scutellum strongly sculptured
with broad median groove anteriorly.
Proacrias will be most difficult to separate from
Pediobius.
Both genera have the propodeum with paired median carinae which
diverge posteriorly. Both genera have a plica on the propodeum,
although this is generally more distinct in
Pediobius.
Pediobius always has a
distinct collar on the pronotum, this collar can be present or
absent in
Proacrias.
Proacrias has 2 funicular
segments, while
Pediobius
usually has funicle 3-segmented. In
Pediobius
the postmarginal vein is quite short; in
Proacrias the
postmarginal vein is variable, but can be longer than the stigmal
vein. One character that seems to be able to separate these genera
is that in
Pediobius the
median carinae on the propodeum, after diverging, continue without
turning to the posterior margin of the propodeum, there is a complete
carina on the posterior margin of the propodeum between the median
carina and the plica, and the posterior margin of the propodeum
is extended into a small neck (nucha) medially. In
Proacrias
the median carinae turn back posteriorly rather abruptly and define
a trapezoidal area, there is not a carina along the posterior
margin of the propodeum, and the posterior margin of the propodeum
is not extended into a neck medially.
A key to the 4 species is provided by
Boucek
(1977).