Triorophus sp.

Housing:

Any container at least 20 oz in size, with more width than depth, (but still with at least 1-2 inches of depth) will work well for a starter colony, and you can upgrade the enclosure size a bit as their population grows. None of the life stages can climb, so a tight fitting lid is not necessary.

For the substrate, a layer of fine sand 3-4 inches deep should be provided, you can mix in a small amount of coconut fiber if you want, but that's not necessary. On top of the substrate I like to offer a thin layer of dead hardwood leaf litter, which larvae will slowly nibble on. Hides in the form of small curved bark pieces, cardboard rolls and/or eggcrates should be provided for the adults.

Most of the main enclosure should be kept very dry, with a third or so of the substrate being kept moist at all times. You can go with a horizontal humidity gradient, or, if you have enough substrate depth, a vertical humidity gradient, (which would probably allow for more larvae to pupate in the communal enclosure successfully). They should be given a very high amount of ventilation, as per usual for desert dwelling Tenebrionids, in fact you could probably get away with keeping them in a lidless enclosure, provided the substrate is an inch or two below the top of the container.

Diet:

Dog/cat/chick feed serves as the staple diet, leaf little will also slowly be nibbled on by the larvae (but seems entirely unnecessary). Fruits and veggies usually go ignored.

Temperature:

They breed best at temps from 75-85F°, though they may still breed at slightly lower temps, albeit at a reduced rate.

Breeding/Life cycle:

Adults can live for at least a year, which is pretty good for such a small Tenebrionid. Females lay dozens of eggs during their lifespan, and seem to lay mostly in the warmer months of Spring and Summer. The eggs take less than a month to hatch, the resulting larvae take 2-4 months to mature, and then they spend a couple weeks or so as a pupa, before molting into a soft, teneral adult. Adults seem to take a very long time to completely darken, maybe a month or so, but they harden up very quickly. So in total, the time it takes to get from egg to adult is around 4-5 months under optimal conditions.

Ideally, in a large enough enclosure with a proper humidity gradient, larvae will successfully pupate and mature in a communal setup. However, if for some reason there are too many individuals in the enclosure, or the enclosure is too small, has an improper humidity gradient, etc., you may need to isolate larvae yourself to induce successful pupation. 

To do so, remove fully grown larvae (which will be almost an inch in length) from the main enclosure and isolate them in 2 oz deli cups with minimal to moderate ventilation, and an inch or two of moist, compressed sand, or sand and a tiny bit of coconut fiber, (the coconut fiber helps to retain moisture, and keeps the substrate just a little fluffy, which helps prevent pupal cells from collapsing if you overwater them). Leave them be and don't feed them, just make sure the substrate stays moist, but not wet.
It may take a while for the larvae to decide to pupate, and some may die before doing so, however the survival rate during this period and of the pupae is pretty high in my experience.

After the adult beetles eclose and darken up a bit in color, they usually dig their way to the surface. They should immediately be removed from their humid deli cups, and can either be isolated in a "hardening" container with mostly dry sand substrate and a moist corner, or they can just be placed back into the main colony right away. The benefit of keeping them isolated while hardening is that they are less likely to be stepped on by their tankmates in their teneral state, causing permanent dents and such in their soft exoskeletons.
However, the adults of this genus have rather thick and sturdy exoskeletons even when teneral, so as long as they've been mature for a couple days, it's usually safe to place teneral individuals right into the main colony after they've turned a dark orange color.

These little beetles are quite interesting little US natives, and I hope they become more popular in culture as time goes on!