What in the world is this strange creature?
The point breakdown* will be as follows:
2 points for order
2 points for family
2 points for genus
2 points for species
2 points for describing the behavior
As in past weeks, you have to be first in each category.
*What are Myrmecos points good for? The cumulative winner at the end of the month gets to choose either 1)any 8×10 print from alexanderwild.com, or 2) a guest blog post on a topic of their choosing.
[update]: the answer is here.
Myrmecos Blog 
Hymenoptera: Formicidae: Cephalotes
The ant is blocking the nest entrance with its head.
Just a wild guess, one of those goofy Cephalotes (Hymenoptera, Formicidae, Myrmecinae?) that plugs its nest with its head?
I’m guessing the species is Cephalotes rohweri?
Im thinking more along the lines a of Colobopsis, but the nest plugging activity I agree on.
I have looked closer at the image and I have changed my mind, I am now going to go with Cephalotes as well. If taken in Arizona it must be rowheri. So Hymenoptera, Formicdae, Myrmicinae..
I had no idea, but now…cool beans!
for some reason those girls always reminded me of alien xenomorphs
vs
There are similar tunnel-blocking spiny disks at the fore and aft regions of scolytine weevils, but given the context this must be an ant. Did you check for flying ability by dropping it from a treetop?
I’d say it’s Cephalotes varians. Soldiers of C. rohweri don’t have the “head disc” complete.
NOONE ELSE SEES THE ALIEN SIMILARITY???
Argh, I’m late and everything has already been covered. Can’t even think of a way to cheese a bonus point!
Just a minute here! How can we identify this mystery creature from a single photo, after the earlier chastising we got about that? Anyway, I perceive the structure as convex rather than bowl-shaped, and thus it must be a Microdon larva!
Diptera: Syrphidae “[i]Microdon illusio-opticalis[/i]”. These live with [i]Cephalotes[/i], and sometimes even provide nest entrance blocking services (in exchange for eating their larvae).
Are you going for the coveted Adrian Thysse award?
Yeah, I got in too late to make points any other way.
So sad! 😦