Division of Zoology, University College, Thiruvananthapuram-695 034, Kerala, (India).
The coconut pest Rhynchophorus ferrugineus Oliv. showed the presence of seven larval instars when reared in the laboratory on sugarcane. The log of head capsule width of each instar when plotted against the instar number exhibited a hyperbolic curve. This implies that Dyar's rule does not hold in this case, presumably due to the high growth ratios exhibited by early instars.
