These are images of an Earth-Boring Beetle that is most likely a female Bolbocerastes imperialis.
Full Size Image: Click Here
SEXING INFO:
(I sent a message to Robyn Waayers asking for sexing info about this species and this is what she replied)
"Here is what Ron McPeak wrote to me several years ago regarding sexing Bolbocerastes regalis and B. imperialis. Many of my images on Bugguide confirm these descriptions."

"Males [of Bolbocerastes regalis] have a single, truncate (sometimes binodal), horn that is well forward of the eyes and drops straight off to the mandibles and anterior edge of clypeus.
Females have two horns. The large medial horn is truncate and barely forward of the eyes. From this horn it sweeps forward to another horn that is usually not very elevated (the forward horn on the female is where the single horn on the male is located).
Male Bolbocerastes imperialis have a single horn that is almost pointed (not truncate as in B. regalis). Female B. imperialis have an anterior horn that is also almost pointed and is much narrower than the median horn. The horn in male B. regalis is wide and truncate: in the female both horns are truncate and of similar width."

So, simplified, males have one horn and females have two.