Oh thanks! I get lots of Xylomya adults in my house all summer. Do you think it could be that genus? Any tips on rearing them?

Okay, I'm a few years late on answering this -- just seeing it now. :)
I raise lots of Hermetia illucens (Diptera: Stratiomyidae). They are quite easy to raise.
The larvae need "muck" to eat. In my yard, they eat the birdseed that has fallen to the ground, gotten damp, and is moist and rotting. I generally wait until they are prepupal before bringing them in, but I've also brought larvae inside to rear.
I provide prepupal larvae with shallow dishes of soil substrate as well as leaf litter. I rear these guys inside mesh butterfly cages. It may be necessary to use a fine mist sprayer to keep some moisture in the cage if conditions are dry where you are rearing.
Eclosion generally occurs two weeks after pupation.
For adults, I supply butterfly sponges: cellulose sponges soaked in half clear gatorade / half water. This allows them to "nectar," which I see both in captivity and in the wild. Adults don't live long, so it's essential to allow them to mate.
I'm sure you know that these guys are considered beneficial insects in that they break down compost. Fortunately, they are quite easy to raise and, of course, quite beautiful.
If you have any questions, please let me know!