The cockchafer (colloquially called May bug, doodlebug, mitchamador, 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 had been nearly eradicated in the middle of the 20th century through extensive use of pesticides and has even been locally exterminated in many regions. However, since an increase in regulation of pest control beginning in the 1980s, its numbers have started to grow again.
Imagines (adults) of the common cockchafer reach sizes of 25–30 mm; the forest cockchafer is a bit smaller (20–25 mm). The two species can best be distinguished by the form of their pygidium (the back end): it is long and slender in the common cockchafer, but shorter and knob-shaped at the end in the forest cockchafer. Both have a brown colour.
Male cockchafers have seven “leaves” on their antennae, whereas the females have only six.
The species M. pectoralis looks similar, but its pygidium is rounded. The cockchafer should not be confused with the similar European chafer (Rhizotrogus majalis), which has a completely different life cycle, nor with the June beetles (Phyllophaga spp.), which are native to North America, nor with the summer chafer (or “European June bug”, Amphimallon solstitiale), which emerges in June and has a two-year life cycle. (All of these are Scarabaeidae, have white grubs, and are turf pests. source