A sensillum is a tiny part on an insect's body that helps it feel things like touch or smell.
Sensilla are very small and important for insects to understand the world around them.
Examples:
The bee's sensillum helps it find flowers.
The ant's sensillum can feel the ground.
The sensillum on the fly's leg helps it know if it's on food.
The sensillum on the bug's nose is very big!
The sensillum on the butterfly's wing can feel the air.
The sensillum on the spider's foot is very sensitive.