Data from populations of Anticarsia gemmatalis Hübner larvae, and simulated data considering fixed and variable proportions of larvae head capsules sizes of successive instars, were fit into a segmented polynomial regression. The joint points corresponded to the change of instars and the larvae growing process was represented by a sequence of submodels. This allowed the accurate estimation of the mean size of larvae head capsule, and the confidence interval for each instar.
Insecta; head capsule; insect development
