Hi sunshine_qld, they were in a half glass bowl (top open) which is mostly filled with large rocks so the plants are at the top and get enough air circulation. they are dried on a flat surface before being placed back. thank you you very much! are they toast?

Yes, it's probably rot and they are dead. Bulb type tills are sensitive to watering inside the bulb, when conditions are not optimal (low light / temperature / air flow). During winter season I recommed misting their surface only, don't let much water get inside the plant.
What temperature range are they placed in?

Hi raxidor, thanks for the recommendation. I have mostly bulb type tillys and I will be absolutely heartbroken if I lose any more. From now on I'll just be misting them. I can't get myself to throw these two away yet. it's just so horrible what happened. Both were doing so well with new leaves coming out. And I was looking forward especially to nursing the "adolescent" caput medusae to adulthood. They have gone completely limp now. There's yet another caput medusae that seems to have lost leaf turgor but there's no colour change or soggy feel...yet... I set the temp to 75-85F but there's no good control. I am often shivering or sweating. :((

75F temperature is fine. My plants have 64F over night and 73F over day during winter. So some water probably stayed too long inside your plants.

so, i might have kind of solved this mystery. these two plants were kept in containers in other location till the fateful saturday. Right next to this container is a large t. cyanea with leaves extending to this pot. I water it by drenching it under a tap thoroughly till water is running down the leaves. it was just so odd seeing two plants right next to each other in the same spot affected this way that i think it the death might be site- specific. And i am guessing that it was water dripping down the cyanea leaves onto these two hapless plants that did them in. looks like i had an accomplice. Usually there's a schiedeana and a fuchsii v. gracilis in that spot which may have got lucky that day. So, in short, I'll mist my bulbs as well as be super careful about where I put them. Thanks, guys. hope i don't turn into a "serial killer".

Glass contains promote dampness. My suggestion would be to use wood or stone for mounting tillys like these. They may appear dry to you but soaking once a week is a bad way to treat the plants. They are called "air plants", they need air circulation above all else. Winter is a tricky time for these plants. I dont soak any plant unless the temp is about 80F consistently outdoors.

Do you not soak all your tillandsias in winter time? Not even the mesic types like T. juncea or T.capitata?

Thanks, HD, that's good to know. Mora, juncea, cyanea, gracilis, karwinskyana and even my caputs show brown tips which led me to think they need a good soak. Just the schiedeana, butzii, bulbosa and caliginosa look perfect. Xerographica came in a poor shape and has many dried leaves. Perhaps misting more frequently would be the solution. And then if it's air circulation thats the main problem, then would drying them in front of a big fan help. Usually that dries them out super fast. Thanks a lot!

DON'T!! I learned the hard way...

Unless it's really warm where you are I guess. It's winter for me, cloudy days and indoor temp around 20 deg C. I had a xerographica rot and die a few weeks ago so I panicked and thought I should put the other xerographica and seleriana (hard to dry thoroughly ones) in front of the fan. Turns out the combo of wet and cold (fan was just blowing room air, not heated) caused them both to die too. I am devastated. I don't want that to happen to you... :(

Goodness, Iris, sorry to hear that you lost your plants as well. Thanks for the warning.

So, i misted my plants yesterday, just outside and avoided the inside. Today 5 selerianas have died. They were on a flat surface to dry with slight inclination. These plants look so ghastly when they die...it's like straight out of a horror film.

I'm sorry to hear that...

This video about winter watering just came out from a very useful youtube channel I follow. Lot's of great tips (and also look at the size of the plants they have in their greenhouse!!)

Winter watering (Planta Brutt)

Thanks a löt for sharing that video, Iris. I went through many of their videos to learn more about specific airplants that i wanted to get at one time. It's been winter here in MI for quite some time now and I only water my plants once a week and take care to drain the water from bulbs or crevices and dry them carefully. Things were just dandy, most of the plants had new leaves coming out, and now, all of a sudden, death and destruction. Could be the sunlight pr could be that the plants have gone dormant. Frankly speaking I don't know. I am going to lightly water the plants once every two weeks except for the mora, cyanea, bergeri, schiedeana, gracilis and the ionanthas which I would continue on a weekly watering schedule. Here's wishing no one loses another airplant this winter (or ever).