Saw stag

Donation in City Folk
Blathers will comment on your donation as follows: "The saw stag beetle's most distinguishing feature is its large, curved jaw, wot? The larger the specimen, the more teeth in its jaw. Among collectors, the teeth settle a specimen's worth. I don't suppose bugs have dentists... Hoo, I'm quite sure that would be the worst job of all time."

Encyclopedia Information
The encyclopedia in City Folk says: "Though typically nocturnal, these can be found during the day."