THE WHITE-PINE WEEVIE 



195 



In from 6 to lo days the eggs hatch and the young larvs burrow 

 downward beneath the bark, feeding upon the cambium layer. As they 

 grow larger they consume all of the inner bark and cut furrows into 

 the wood. As soon as a larva is full grown, it turns into the pith and 

 there forms a pupal cell, or if the pith is already occupied by other 

 larvae it will make a cell beneath the bark and roof it over with shreds 

 of wood. In about 30 days after hatching from the egg the larva trans- 

 forms to the pupal stage. This lasts for nearly two weeks and then 

 the transformation to the adult takes place. The adult remains in the 

 pupal cell for a week or more and becomes thoroughly hardened before 

 chewing its way through the wood to the outside. 



Fig. 2. — Seasonal history of the white-pine weevil, Pissodes strobi Peck 



After feeding on the new shoots of the pine for some time, these 

 newly emerged weevils seek out a place in the litter beneath the trees 

 and hibernate until the following spring. 



Distribution 



The white-pine weevil is distributed over the entire range of the 

 white pine, occurring in some sections much more abundantly than in 

 others. The map sliows tiie per cent of weeviled trees found in the 

 most heavily infested stands of young pines in the various sections of 

 the white-pine region.'' Tl will be sctn that there is a heavier infesta- 



' For these data I am indebted to correspondents in the different sections. In 

 Minnesota some of the figures are from personal observations and the rest were 

 obtained through the State forest rangers. 



