The reproductive cycle offemale Anguisfragilis from Isle of Portland, Dorset, appears to be biennial. Fewer small females were reproducing in 1977 than in 1979 and the ratio clutch size: body size showed more variability in 1977. It is considered that the droughts in the summers of 1975 and 1976 had an adverse effect on A. fragilis reproduction in 1977. Total carcass energy in females about to give birth is much less than in females which are not reproducing that year. The ratio energy in clutch: total energy in body varies from 0.29 to 0.38.