These are images of an Earth-Boring Beetle
that is most likely a female Bolbocerastes imperialis
Full Size Image: Click Here
(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