Over 4 inches, the back board of the bird house is 3/4 inch thick.
That’s not even close to the ones in Biology. Bet they came from South America, or Asia. The abdomen on those was about an inch thick.
I’ve been searching the web, and haven’t any hoppers that big. It’s been 50 years since biology class. May they weren’t technically grasshoppers? Only something that looked grasshopper-like. And who knows how long the were sealed in those bottles of formaldehyde?