Famous Riddle--new to me--HELP!

I am new to koans, and my friend has just given me a riddle to solve before he will return the money he owes to me. Won’t you please help? The riddle is this: Homer asked the children what they were doing and this was their reply: “All we saw and caught we have left behind, but all we neither saw nor caught we bring with us.”

Q: What are the children talking about? Which philosopher was commenting about which poet?

Your time and consideration of this question are most appreciated. Thank you in advance.

i believe the answer is lice/vermin and it comes from a story attributed to Herodotus which says that Homer killed himself after not being able to solve the children’s riddle