Cockchafer

The cockchafer (or may bug, as it is colloquially called, or sometimes billy witch or spang beetle, particularly in East Anglia) is a European beetle of the genus Melolontha, in the family Scarabaeidae. Once abundant throughout Europe and a major pest in the periodical years of "mass flight", it has been decimated in the middle of the 20th century through extensive use of pesticides and has even been locally exterminated in many regions. However, since a change in pest control beginning in the 1980s, its numbers have started to grow again. from wikipedia