Moved from Chrysis.

Keyed to species in Bohart & Kimsey 1982(1). I was unsure of one critical character, whether the distal margin of T3 was "bicarinate/double edged," so I keyed both ways at this junction. (If anyone can explain this character or show some photos illustrating it, that would be wonderful!) T3 had four distal teeth; the mesopleuron was not dentate, and the metanotum lacked a spoon-shaped projection. That took me to the 'T3 bicarinate or not' couplet. If I followed the 'not bicarinate' direction, I arrived at C. pellucida (frontal carina was prominent and LID [least interocular distance] was greater than eye height; the midocellus was clearly lidded behind). I eliminated pellucida based on several characters: my specimen did not have the "unusually short and broad" face described for that species, nor was F1 [the first flagellomere] 1.5-1.6x as long as F2 or F3, nor was the malar space only 1.3 MOD [mid-ocellar diameter]. I returned to the couplets in the 'bicarinate' direction. The lack of a strong longitudinal carina on T3 ruled out C. dugesi. The combination of the long malar space (close to 2 MOD) and the lidded midocellus ruled out the venusta group. I considered remissa, which has a more eastern and southern range and is not known close to MT; I ruled this species out based on its shorter malar space (1.3x MOD), rather angular median notch distally on T3, and 5-6 mm length, none of which matched my specimen. That brought me to the antennalis group, where the strong "saddle" on T3 in lateral view, along with size, range, and darkened wings ruled out the other possibilities and took me to C. antennalis. MT appears to be near the edge of the known range of this species; Bohart & Kimsey mention marginal records from Florence, MT, Mayfield, ID, and Robson, BC. Species description matches well, including typical size of 6-8 mm. It appears that relatively few Chrysis species have such a strong "saddle" or depression on T3 in front of the pit row; based on available lateral images from BugGuide and the UBC entomology collection (not representing all species, of course), the only other species I found with this feature so well-developed was C. oculata in the UBC collection (and this is a species of India!).

Chrysis antennalis biology: Bohart & Kimsey 1982 record several hosts for this species, all wasps in the Eumeninae, within the genera Ancistrocerus, Microdynerus, Odynerus, Parancistrocerus, and Stenodynerus (eg. this September observation from the same site).