MODEL FOR THE IMPORTANCE OF EXOGEN FACTOR S INFLUENCING THE VARIABLE DORMANCY OF PRAEPUPAE OF CEPHALCIA-ABIETIS (HYMENOPTERA, SYMPHYTA, PAMPHILIIDAE)

Praepupae of the web-spinning spruce sawfly, Cephalcia abietis Linnaeu s 1758, rest in dormancy in the soil for 6 months up to 5 years. The e nd of prediapause is indicated by the development of the complex eye. This stage needs a period of chilling for further development, i.e for pupation. Factors responsible for annual changes of the temperature i n the prepupal chamber are the following: weather, soil condition, veg etation and the behaviour of the individual larva.