Morphology of different development stages from egg, larva, pupa to adult （male and female） of the firefly, Pyrocoelia pygidialis Pic, was described in details. Some biological habits were noted according to the records of field collection and observation, with references to the rearing in the laboratory. With weakly luminous egg, larva, pupa and female adult, and much weaker luminous male adult only when disturbed, P pygidialis Pic is considered as a diurnal firefly, and chemical signal, instead of light signal, is possibly its dominant means of male-female recognition.
