Biometrical Analysis of Leucinodes Orbonalis Guenee on Pea

Studies on biometrical analysis were carried out to test the applicability of Dyar's law to the larvae of Leucinodes orbonalis, when reared on pea at a constant temperature of 26±1⁰ C. The measurements of head capsule width of the larvae fall into five well defined groups each indicating an instar, when larvae were reared on pea. The mean values of the observed (0.21 to 1.30 mm) and calculated head capsule width (0.22 to 1.35 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 pea and it followed the Dyar's law. The progression factors determined from the body length and width indicated great deviation. The multiple correlation coefficient (R²=0.982) also indicated a very high predictability of head capsule width through larval body length and width.