The reproduction of Ips typographus L. and Pityogenes chalcographus L. in the pine forest is shown in detail partially in time lapse including the boring action of the male, the preparation of the mating place, mating, creation of the female's passage and egg niches, egg laying, transportation of boring dust, larval development, pupa stage and leaving the bark. Places attacked by the insect and damage in the open are shown as well as the significance of the beetle in natural pine woods and commercial forests. The influence of predators on Thanasimus formicans L. is shown.