Onthophagus from Panamá

Hellow friends:

Please can you help me with the identification of these Onthopagus ?, the pictures are not very pretty because in this moment I have not a good camera and I don't want to extract it out of the pins for not damaging more the specimens, I think that are two species of Onthophagus apparently ?, these are the Canal Zone in Panama, if somebody knows these species I will thank your help.

cordial Greetings
Carlos

Onthophagus sp. Picture 1:
<a href="http://www.servimg.com/image_preview.php?i=5&u=11746402" target="_blank" ><img src="http://i44.servimg.com/u/f44/11/74/64/02/scarab10.jpg" border="0" alt="Image hosted by servimg.com" /></a>

Onthophagus sp. Picture 2:
<a href="http://www.servimg.com/image_preview.php?i=6&u=11746402" target="_blank" ><img src="http://i44.servimg.com/u/f44/11/74/64/02/scarab11.jpg" border="0" alt="Image hosted by servimg.com" /></a>

Onthophagus sp. Picture 3:
<a href="http://www.servimg.com/image_preview.php?i=7&u=11746402" target="_blank" ><img src="http://i44.servimg.com/u/f44/11/74/64/02/scarab12.jpg" border="0" alt="Image hosted by servimg.com" /></a>