Coelus ciliatus

This caresheet is almost certainly applicable to other Coelus species, I've just only ever kept C.ciliatus.

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Housing:

Any container about gallon in size, with more width than depth, (but still with at least 3-4 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 should be a layer of dead hardwood leaf litter, which seems to be an important part of their diet. No hides are needed for this genus, both adults and larvae spend almost all their time underground, their substrate provides them with all the cover they need. 

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 dune 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:

Decaying hardwood leaves make up a large portion of their diet, and they also enjoy dog/cat/chick feed. Fruits and veggies usually go ignored.

Temperature:

They breed well at temps from 70-76F°, any higher might result in a slight larval die off.

Breeding/Life cycle:

Adults live for 6-12 months, it's hard to tell just how long when you've got a good sized colony with overlapping generations, but I don't think any of my adults lived more than a year. Females lay dozens of eggs during their lifespan, which are very large in comparison to their bodies and oval in shape. The eggs take less than a month to hatch, the resulting larvae take 5-6 months to mature, and then they spend another month or so as a pupa, before molting into a soft, teneral adult. So in total, the time it takes to get from egg to adult is around 7-8 months. 

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 from the main enclosure and isolate them in 2 oz deli cups with minimal ventilation, and an inch or two of moist, compressed sand, or sand and 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 comparison to some related genera.

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, and since they spend most of their time underground, 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!