Answer:
I was more or less uneasy until I found out what they were, but now I saw they were grasshoppers, they set me on the war path.
Step-by-step explanation:
Sarcasm is simply using irony to mock or make jest of something/someone. The writer used sarcasm here to convey his thoughts and feelings about the ants. He used irony to talk about going to war with the ants when he clearly meant something else.
He was trying to ridicule someone by declaring that he was uneasy at first before declaring all out war when he discovered he was dealing with ants.