The face really fooled me...looked more like a bee or wasp to me than a beetle. Then again, I didn't take a close look at the mouthparts in the field...which in most bees would have hefty triangular mandibles.
Two things to note in this image: the ("one-sided" mono)pectinate female antenna; and the barely visible intimation of serration on the outer edge of the tibia...the latter being a distinguishing character for R. rex
, according to a remark on pg 208 of Evans & Hogue(1)
. (A cropped detail of the tibia above appears as the 6th image in this series, within a collage of crops from other images of this ripiphorid.)
In contrast, male Ripiphorus
have "bipectinate" antennae (i.e. with two
flabella emanating from the base of each antennal segment...rather than the one
flabella in the female). Thus male antennae look a lot more "busy", having generally twice as many flattened, elongate flabella. Compare my female here with the male images below:
For more complete info on this post, see 1st image in the series.