RMDC wrote:We've just found some caterpillars in our yard, and we have two young daughters who would flip to watch them grow. What are the essentials we'd need to do what you're doing?
OHHHH how cooool! I wish I had kids, or had friends who had kids who were even remotely interested in bugs lol
I'd say most importantly find out what kind of caterpillar they are and then find out what they eat!
Usually what ever plant you found them on is a good indicator of what they probably like. I left mine outside in that basin covered with some mosquito netting until they got pretty big. and then collected some into that bucket contraption I made. I still give them food. I buy organic potted cilantro for mine because I don't have anything I can feed them anymore in my garden but If you have plants they're eating you can just uproot some or give them fresh cuttings everyday.
I have like WAYYYY too many to keep all of them so I just took as many in as I could comfortably feed and house. So I'd say let them pick out which ones they want and shack them up. I hear that some people use an old fish tank with a screen top or anything like that, as long as there is enough ventilation and you can wipe up the bottom of the cage at least once a day it should be ok. Def don't use any kind of container you're going to be punching holes into for air.
Everything I used cost me under 10.00. (aside from the food itself)
My garden was in a old metal basin, the mosquito netting I used was from one of our camping tents. I didn't cut it or anything, just draped it over the basin. The bent arches I have in it were just scrap metal my dad had in his shed, I'm pretty sure they are the wall mount pieces for those wire shelving units.
The bucket cage was just a Bucket and lid, I cut the top of the lid out with a Box knife and hot glued some screen over it. I got it at Lowes if you have them around you but any hardware store should carry door screen replacements, I think the 15 foot roll was around 5.00 (shame I only needed about a foot of it)
The door of the cage is basically the same thing, i just cut out a square, cut two squares out of that to make a frame, hot glued the screen around it and hot glued two metal hinges on it.
It's really not an exact science, There are a ton of good guides I've found online.
Just see what you have laying around the house first, it doesn't take much.
Oh, and don't forget not all caterpillars go into their chrysalis the same way, The black swallow tails hang back on an angle and make a little sling to support themselves, so I have to put in a bunch of angled sticks for them. And I know Monarchs can hang from stuff like the top of the cage and they make a "J" shape as they change.
You should post some pics of your caterpillars too so we can check them out!!
I'm interested to see them!
Here are some helpful links I used when I was researching
http://www.butterflyschool.org/teacher/raising.html
http://www.wikihow.com/Raise-Butterflies
http://bugguide.net/node/view/203352 (The cake pan cage on this page is brilliant!)
http://www.butterfliesandmoths.org/identify
I found 3 dead smaller ones.. I'm hoping it isn't some of the plants I got them.. They were supposed to be organic and I washed them but who knows.. I removed the Parsley that they were near. 
No one else seems to be sick though and they're in love with Cilantro! 
If we can find a suitable container, I'll definitely put some pictures up.