Gordon doesn't mention either gender showing a pale head as far as I'm reading, but I guess its the default for this genus.

Moved from Brachiacantha.

I too thought initially this one was Brachiacantha. But after consulting Gordon's ref.(1), it didn't quite seem to fit a particular species (B. decora would be the closest). This ladybird has completely dark humerals, which seem always have a bit of color in similar Brachiacantha. Checking the key to the tribe, Brachiacantha always has a spike or spine on the protibia, whereas Hyperaspis (and others) does not.

Given that this is Hyperaspis, there appear to be several similar looking candidates. H. medialis Casey appears most likely, and is recorded by Gordon only from Brownsville and Alpine, TX. H. conspirans Casey also appears similar, especially as Gordon notes the anterior margin of the apical spot is usually emarginate. Gordon's key separates these two by location, with H. medialis from TX and H. conspirans (and a couple others) from AZ and NM. However, in the description for H. conspirans he specifically mentions "TX: Brewster Co., Chisos Mts." For H. conspirans he states "male head with base of vertex black, female head entirely black." Given that, and your Brownsville location, I'd say we go with H. medialis. Either way, it's another new species for BugGuide :)