Spiders that provide their young with milk

Here's how it goes. The mother spider lays a clutch of eggs, typically between 2 and 36. When the babies hatch, the mother deposits tiny droplets from her epigastric furrow, the opening on her abdomen from which she lays her eggs. The newly hatched babies sip from these droplets from the first few days of their life; but as they gain a little bit of size and strength, they are able to suckle directly from the mother's epigastric furrow.

The scientists aren't sure exactly what the milk is made of, but suggest it could be liquefied, unfertilised eggs. Some other animals feed their young with unfertilised eggs - frogs, for instance, and bees, although generally the eggs are laid as per normal, and the young just eat them.

https://www.sciencealert.com/some-jumping-spider-mums-nurse-their-babies-on-spider-milk-and-this-is-the-cutest