The numbers of queens, workers and larvae were recorded for a sample of hibernating colonies from five different species of Myrmica. The larvae were divided into three size classes. The frequencies and distribution of larvae within these size classes have been compared between species and between queened and queenless colonies. A sample of each larval class was reared to the pupal stage and the resulting castes were recorded. The Discussion compares all the species with Myrmica rubra and attempts to explain the differences observed for the different species.