Zephyranthes, also known as rain lily, propagates through producing offsets or through seeds.
However, from my experience, Zephyranthes Citrina, bright yellow-coloured rain lily, do not produce offsets, but will produce 10-25 seeds from one seedpod.
My first experience with germinating seeds from Z. Citrina happened more than a year ago ... I was trying my luck by just planting the seeds in a pot next to my Agavae.
The seed pod, just splitted and ready to be harvested

The seeds, there were 12 seeds from the one and only seedpod, harvested on 16th July 2008

Then, a week later, to my pleasant surprise, needle-like leaves were seen growing

And on day 17, they grow even longer ....

And this is on day 37

Then I moved them to a bigger pot and forget about it. And they still survive without much care from me :-)