Relative Growth of Mandibles in Stag-Beetles (Lucanidae)*.

Linear measurements of length of mandibles and body (or. elytron) made by Brindley, myself, and Dudich, respectively, in the males of three species of Lucanidæ, have been analysed. It is shown that the simple heterogony formula y=bx“, where y= mandible-length, x=” total “length (mandiblelength+body-length), and b and k are constants, provides the basis for an expansion of mandible-growth. The values of k are, for L. cervus about 2–3, for L. lunifer about 1.55, for Cyclommatus tarandus 1–97.