Morphometrics and Morphology of Rice blue beetle Leptispa pygmaea (Baly.): (Coleoptera:Chrysomelidae)

The minor pest, blue beetle, Leptispa pygmaea (Baly.), is attaining status of a major pest by causing much damage to different crops in India. Attempts were made to study morphometrics and morphology of the beetle for correct identification and management. The beetle was found to lay oval eggs; measuring 0.20 mm length and 0.12 mm width hatching into creamy white grubs with two spiny projections on head and two tubular projections on posterior end of the body. The head capsule of all five instars measured 0.17, 0.20, 0.23, 0.26 and 0.26 mm wide, respectively. It pupated on leaves while attached loosely by its posterior end. The brown pupa measured 3.89 mm (length);1.32 mm (width). The adult beetle was metallic greenish yellow with longer antennae, narrow thorax and a long body. The female beetle could be differentiated by its shorter antennae, broader thorax and stouter body. The antennal scape was broader in the female compared to that of the male. The male and female reproductive system included aedeagus (length of 1.36 mm; width of 0.07 mm (anterior) and 0.10 mm (posterior)), two parts of tegmen, siphon and spermatheca with two lateral coxites (1.60 mm long; 0.52 mm wide), respectively.