Painted Lady Caterpillar Vanessa cardui

The caterpillar of the Painted Lady butterfly is mainly black with a distinctive pale yellow line along its sides and black and yellow spikes.

The caterpillar makes a tent of silk, in the above case combined with "wool-carding" from the furry leaf, to protect itself while feeding (usually on thistles) and also, later, to pupate. The caterpillar shown immediately above is a younger stage than those further above and has parallel yellow lines along its back.