worm
虷 centers on a worm, specifically a mosquito larva or wriggler. The meaning is narrow and concrete, referring to a small aquatic insect larva.
虷 combines 虫 (insect) with 干, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound for a type of worm or larva.
The insect radical 虫 on the left and the dry-looking 干 on the right suggest a worm that lives in dry places, but actually it's a mosquito larva that wriggles in water. Imagine a tiny worm-like creature with a dry, stick-like body.
For カン, picture a can full of wriggling mosquito larvae: can -> カン, and the can is teeming with these tiny worms.