This 2nd image gives a slightly different angle of view, which will hopefully be helpful in discerning the "coxal projections", mentioned below.
Again, the red arrows point to two relatively large, downward-pointing, conical projections at the inner bases of the forelegs. (They are somewhat dark and difficult to make out.) I'm interpreting these as the "densely hairy elongate projections on the inner side of the front coxae at apex" mentioned in reference to R. rex
as a "significant character of the species" on pg. 17 of Vaurie(1)
. Note that the beetle's right palp is partially blocking the view of the conical projection at the inner base of its left foreleg.
All this may be difficult to see in the 560 x 420 pixel image above, but will be more discernible in the full-size 2907 x 2178 pixel image here
The green arrow points to what looks to me like a small suture-separated leg part at the base of the femur, which I'm speculating may be the (smallish) trochanter here. And, again, the two much larger dark-brown triangular-to-conical objects (between the green arrow and the bottom of the head) I'm taking as the elongated coxae. This is my best attempt at interpreting the anatomical homologies here. I'd very much appreciate correction or confirmation here, from those who may know for sure!