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Information on some aspects of the life-history and distribution of Coccinella undecimpunctata L. in Britain is lacking or inconsistent. The authors review the literature and compare the results of their studies with those of other workers. Adults were collected from sand dunes in Sussex in August 1969 and observations on the duration of the developmental stages were made on their progeny, which were reared under room conditions. Leaves of various species including Rosa and Prunus were provided for oviposition and most eggs were laid on the upper surface; oviposition occurred only on bright sunny days. The eggs hatched in 4-6 days and there were four larval instars, lasting 4-5, 4-7, 3-4 and 9-11 days, respectively. There was some evidence that there are normally two generations a year, with the possibility of a partial third. Both larvae and adults fed readily on a variety of aphids but they did not feed on either cow dung or horse dung, which had been reported by O.A.M. Merritt Hawkes and T.F. Marriner to be the larval food. It is suggested that the larvae observed by these authors in tunnels in dung survived by cannabalism and that the adult females had oviposited in the tunnels to provide shade for the eggs. Locality records for Great Britain, based partly on the literature, are shown on a map. This demonstrates that the species is neither restricted to the coastal regions, as had previously been suggested, nor is it exclusively halophilous. It occurs frequently in inland areas in the south-east of England, though the records available for the north of the British Isles are mainly from coastal areas. Its distribution is thought to be determined mainly by humidity, though winter temperatures and sandy habitats may also exercise some influence.
