October, 1929] 



WHITE PINE WEEVIL 



19 



Table III.— Length of the Larval Stage, 1928 

 IN THE INSECTARY CAGE 



IN THE GREENHOUSE 



Number of Specimens . 



leaders taken from the field. In field and insectary material, evidences 

 of cannibalism have been observed when the larvae are crowded and 

 have insufficient food. 



Individuals hatching after most of the larvae have moved down the 

 leader consuming all the available food are in a precarious position. If 

 they are too far from the food supply thej'' perish; if they succeed in 

 reaching food the competition is often too great for them. 



Each larva when nearly mature drops out of line, chews a tunnel into 

 the heartwood and forms a pupal cell. The entrance to the pupal cell 

 is blocked by the chips removed during its construction. Under crowded 

 conditions the inner heartwood is not sufficient to accommodate all of the 



