oil beetle, a type of blister beetle

6162   Hi.  This beetle was found in field behind my house on a sunny day during mid-October.  I live in Port Elgin, Ontario.  I don’t remember ever seeing this beetle before and didn’t see it on your website.  The beetle is fairly large at around 3.5 cm long.   My son has suggested that it may be an Oil beetle. Please confirm.  Andy.  Port Elgin, ON

This is indeed an oil beetle, a type of blister beetle (Coleoptera: Meloidae) in the genus Meloe. They are called oil beetles because of their habit of exuding an oily fluid (their equivalent of blood) from between their joints when handled roughly. This fluid contains a chemical (cantharidin) that can cause blisters on tender skin. See https://tinyurl.com/y7jhuhrq for more information.   Ed Saugstad, retired entomologist; Sinks Grove, WV.