Biometrical Analysis of Leucinodes orbonalis Guenee on Tomato

The measurements of head capsule width of the larvae fall into five well defined groups each indicating an instar. The mean values of the observed (0.21 to 1.39 mm) and calculated head capsule width (0.24 to 1.51 mm) and progression factors were close to each other which indicated that an increase in head width during successive instar was in geometrical progression, when larvae were reared on tomato and it followed the Dyar's law. The progression factors determined from the body length and width indicated great deviation to support earlier theory. The multiple correlation co-efficient (R²=0.998) also indicated a very high predictability of head capsule width through larval body length and width.