The variation during development in the following characters of Lithobius crassipes is described: body-length, head-length, ratio head-length/body-length and head-length/headwidth, number of coxal pores, ocelli, antennal articles and teeth on forcipular coxosternite, projections on tergites 9, 11 and 13, spinulation on the last pair of legs (DampP on all legs), accessory apical claws on the 15th pair of legs, genitalia and the pattern on the cephalic shield. Also the difference between male and female and the correlation with size within each post-larval stadium are given. The boundary between juvenile and adult stadia and the number of post-larval stadia are discussed. L. crassipes shows a geographical variation in Sweden and can be divided into western and south-eastern groups (W and SE). There are differences between the two groups especially in spinulation and pattern on the cephalic shield. So far there is no decision of their taxonomical status.