How to tell if your silkworm is alive: a flowchart

1. Is the silkworm moving? If yes, go to 2. If no, go to 3.

2. The silkworm is alive.

3. Has it got its tail in the air? If no, go to 4. If yes, go to 5.

4. Examine the back of the creature. You may see a faint grey line beneath its skin, as if it had a spine. Watch this carefully. Does it pulsate? (This, I believe, is the silkworm's main artery, and evidence that it (i) has blood, and (ii) this is being pumped along its length by some sort of rudimentary heart). If yes, go to 2. If no, go to 6.

5. Watch carefully. Can you see a tiny and perfect little black dropping at the end of its tail? (This will teeter for a second, before being expelled a few millimetres away. If the tray were made from metal it would go ping). If yes, go to 2. If no, go to 6.

6. Give the animal a gentle poke with something clean. Does it move? If yes, go to 2. If not, go to 7.

7. Your silkworm is probably dead. If you bury the corpse at the base of a mulberry bush award yourself green points for recycling.