Hi Alex,
good question.
I excluded
Chrysis ragusae for its distribution, because it is known for Mediterranean countries and a few central European ones (e.g. Hungary). Based on pictures it's not easy to separate them.
As you said, the general habitus is really important to discrimate these species.
Chrysis indigotea is a relatively robust and large species in the
ignita group (7-9mm), whereas
Chrysis ragusae is usually a slender and small one (4-6mm, rarely larger) in the
[i]varidens [/i]group. Moreover
Chrysis indigotea has the median area of mesoscutum darker, vs. mesoscutum uniformely coloured in
Chrysis ragusae . Males of
Chrysis ragusae have some antennal segments ventrally gibbous and completely differently shaped genitalia, whereas females of
Chrysis indigotea have a stout ovipositor, vs. normally shaped in
Chrysis ragusae and different placement of the four apical teeth.
In Mayke pictures I cannot see any of these diagnostic characters, excluding the darker median area of mesoscutum and the tip of the ovipositor, which shuold be large and stout, but unfortunately not fully visibile outside. We can ask Mayke to collecte some specimens of take other shots