I’m going to have to make the Monday Mystery harder. Last night’s SEM image lasted all of 6 minutes before army ant expert Gordon Snelling picked the structure (the clypeus) and the family (Formicidae), and another two minutes before Brazilian myrmecologist Flávia Esteves nailed the genus (Cephalotes).
So, six points to Gordon, and four to Flavia.
The SEM depicts a major worker of a turtle ant, Cephalotes pusillus, a common tree-nesting insect in South America. Majors use those massive heads as doors to block the nest entrance, like so:
[thanks to BugScope for the image!]