[Life-cycle of Bursaphelenchus mucronatus Mamiya et Enda, 1979 (Nematoda: Aphelenchida)].

Postembryonic development of Bursaphelenchus mucronatus has been studied. First molt takes place within the egg-shell, and three subsequent molts after hatching. Structure of all juvenile stages are described, as well as molting juveniles and adults. Juvenile stages differ in genital primordium structure, copulatory structures primordial and the body length. In juveniles of 3rd and 4th stage the sex of juvenile was distinguished: male juveniles have cloacal primordium, whereas female juveniles have vulval primordium. Adults differ from juveniles in presence of vulva in females and spicules in males. The key to identify juvenile stages and their sex is given. Male has the terminal bursal flap and 3 pairs of iail papillae: p1 anadanal; p2 and p3 at the bursal flap base: p2 close to mid-line of the ventral body surface, p3 located laterally to p2 at the same level. Unpaired papilla is present on the upper cloacal lip, on the ventral mid-line.