Mallodon dasystomus occurs south of a line from Virginia, Oklahoma and Arizona all the way to South America, but thats not what you have here. Arizona has ALOT of other large interesting Prionids; a subspecies of Archodontes melanopus as well as species of Prionus, Neomallodon, Ergates, Tragosoma, Derobrachus and finally what I think you have here - Nothopleurus lobigenis Bates. Keep shooting.

Note: The abdomen extending beyond the end of the elytra is often a good indicator of gender - female.

I live in East Mesa, and I see these bugs quite frequently during the summer time. I have noticed that they do not like sunlight. Or light at all, for that matter. I have drawn this conclusion because, they seem to be dead if you find them during the day in direct sunlight, and just the other night I found one in my yard, and I shined my flashlight on it, and it seemed to be running away from the light in general. It didn't matter what direction I put the light in, it seemed to run in the opposite direction of the light. Anyway, I'd really like to know what kind of bug this is, because it's become quite the pest around my house. I killed quite a few of them last year, and most of them seem to have gone away for the most part. But now they are popping up all over again. When you smash them, they let out a lot of little white sacks that seem to resemble eggs. I'm assuming that the ones that I keep finding are the females, but I have no way to know for sure. Someone who knows, please contact me at tiger18az@yahoo.com to let me know what this beetle (or whatever it is) is exactly.