The arrows in these two images indicate what I think are the correct anatomical interpretations of the trochanter and coxa of this male Ripiphorus rex.
(Note: I have not seen reference images for this genus, so if anyone knows better, please correct me if I'm in error here!)
The trochanter here looks like a small "flap" appressed against the ventral base of the femur.
The coxa looks like a much larger, triangular-to-conical "flap" located inward from the base of the femur and trochanter, and projecting downward.

Vaurie(1) states that a "significant character" for distinguishing R. rex is:

  "the densely hairy elongate projection on the inner side of the front coxae at apex"

It's clear that the coxae in the images here are hairy. What's less clear is what constitutes "densely" hairy. Without a good reference specimen of R. rex to illustrate the typical degree of hairiness in the species (and specimens of different species illustrating the opposing character state)...it is difficult to say with certainty.

If I had to call it, at first I would have said the hairs look "less than dense". But Edward mentioned elsewhere that this specimen was immersed in alcohol at one point, and then dried. That would tend to mat the hairs and generally diminish the appearance of dense-ness. And after gazing at the images here, I think I can imagine that...before the submersion in alcohol...the coxal hairiness could have been close to that in my specimen below:



And I'd say the coxal projection in the image above qualifies as "densely hairy". So, perhaps up to reasonable variation, the "hairy coxal projection" and "serrate mesotibia" characters are good determinants of R. rex.

Of course, if we do say the coxa are not densely hairy here, than that would indicate the published characters describing R. rex are not consistent with one another...as this specimen seems to have a clearly serrate outer edge on its mesotibia.