Final sizes of the five larval instars of Manduca sexta. The size of the first four instars increase exponentially, but the final size of the fifth instar is about twice (10.75 g) what would be expected (5.39 g) from the regression on the earlier instars. The regression is: weight = 0.0014*e1.66*instar (R2 = 0.999).
Nijhout et al. Journal of Biology 2006 5:16 doi:10.1186/jbiol43