Help Me, Internet Biologists, You're My Only Hope

They should survive the fall, since they are quite light... You do want them hanging to develop normally, but gently touching them should not be bad. Wash hands, etc. or use tweezers. Don't squeeze! You should be able to get the top of the chrysalis to stick in a cotton ball or the like, which you can then pin or tape up. I would avoid putting tape directly on the chyrsalis.

Thanks for the advice. I picked up the two fallen ones, both of which started twitching at one end, which looked to be the end where they had been attached. They're now each dangling by a thread from cotton balls pinned to the sides of the Butterfly Keeper. Hopefully they're not upside down-- it was kind of hard to tell which end was up.

We'll see if that works. Really, though, I'm just thankful I didn't knock the third one down in the process...

Not speaking from a biologist's perspective here, but my sister is a preschool teacher. Wait, no, stay with me. She brought one of these home from the classroom sometime last winter. It stayed in her garage until spring, at which point it blew around the neighborhood a bit one windy day. The darn thing still hatched, so it would seem they're hardier than they appear.

We had the same kit a couple years ago, and we also had a couple (might have been all of them, I don't remember) somehow end up on the bottom of the cage and need to be rescued. They ended up "hatching" (I'm blanking on the term for cocoon emergence!) alright in spite of that. Our problem was we didn't do such a hot job of taking care of them afterward; probably should have just released them to fly and be free ... (we proved juice / sugar water like the instructions suggested, but they seemed to fall or bumble into it, and get their wings gummed up, etc.

Butterfly exhibits often include chrysalises pinned up by the cremaster (usually a pointy or stalk-like tip, and located at the butt end of the butterfly-to-be). So you may be fine, as long as you provide a stick or something similar so that the newly emerged adult can hang from it and pump up its wings.

Incidentally, I once raised some painted lady larvae that I found on thistle in my back yard. There were thistle stalks in the cage when they pupated, and one of them wriggled so hard that it punctured its pupal case on a thistle spine and began to leak hemolymph. I stuck a strip of paper towel over the puncture -- just like sticking toilet paper on a shaving cut -- and it quickly dried there and blocked the leakage. The butterfly eventually matured and emerged just fine.

The term you're looking for is eclosion.

Haha, this post made me laugh (not to be insensitive to SteelyKid's trauma). I know nothing about insects, but I do have a vague memory of having a butterfly thing at school in second grade, with quite a few chrysalises, some of which did fall to the ground. I don't remember any failing to hatch, but one of them was crippled, so take that as the anecdote it is. My teacher just tossed the crippled one in the trash after it failed to fly off, so I picked it out and raised it at home for a couple days, so I imagine I would have thought potentially dead butterflies were the end of the world too, at that age.

Insects are tougher than you think. They did not survive on this planet for nearly 400 million years without a strong will to live. You insects would mature just fine in their chrysalises if they were subjected to far more abuse than a drop to the bottom the cage. The hanging of the chrysalis is a behavior that has evolved to protect the pupating animal from predators. Your butterfly cage is predator-free so the protection is not needed.

As a physicist you might have realized that the terminal velocity of a dropped chrysalis is very low. It could fall all the way from the top of a tall tree and would be unharmed hitting the ground. This happens all the time in the wild. Most fallen chrysalises are found by ground roving predators or scavengers and consumed, but if they luck out they can still mature normally on the ground if it is not too wet.

Actually, a newly-formed chrysalis is quite fragile and can burst if it falls from a great height. Yours didn't, and I am glad for that. SteelyKid would definitely have cried after seeing a burst one.

So now the trick is to make sure they have space to hang after they leave the chrysalis, as they pump up their soft wings. They often hang from the chrysalis itself, with limp wings dangling. That's why I have to disagree with the advice above to just leave them on the ground when they fall. If they eclose on the ground, they won't be able to hang and pump their wings, and they might not ever be able to fly. A curly-winged flightless doomed butterfly is a sad thing to behold, for kids of any age.

My wife did her PhD on a heap of butterflies. She's published a lot of work on endemic Tasmanian butterflies.
Her answers to the questions were:-
The chrysali should be fine for that fall.
The butterflies should be able to hatch fine. They can stand on the bottom of the cage and dry out their wings.
You would be better off leaving them where they were than handling them. They are more likely to be damaged by excess handling.

As long as they have a place to climb they should be OK. How tight are those threads? AROUND them?

You might want to read up and find out how much humidity they need if you are keeping them in a drier-than-the-desert home with central heating. If they need some moisture perhaps you could put a potted plant near them.

And what temperature do they normally develop at? Do they normally winter over outside or do they develop during the summer?