SOME NOTES ON THE BIOLOGY AND ECONOMICS OF SOME BRITISH CHAFERS

SUMMARY Adult chafer beetles do not usually occur in very extensive swarms in the British Isles, and their general importance lies in the characters of the larvae which are notable for their voracity and large size. Another factor of importance is the tendency towards concentration, large numbers of beetles often ovipositing in one field while neighbouring crops remain free. There are few crops which the larvae do not attack, but the damage done by the adult beetles in this country is not important. The distribution, which is local, is shown to be controlled by the sparseness of suitable habitats and by the prevailing conditions of temperature and humidity. The factors which control the varying lengths of the life cycle are also considered to be mainly temperature and humidity. Thus, although Serica always takes 2 years to develop, Amphimattus solstitialis may take either 2 or 3 and M. melolontha 3 or 4 years, according to the conditions controlled by these two factors. Regular flight‐years are usual on the Continent, but are much less definite in the British Isles, and the numbers of beetles appearing are relatively small. It is suggested that the reason for this is the differenc