October, 1929] WHITE PINE WEEVIL 7 



made by the adults. Norway spruce is apparentl}^ resistant although it 

 is a host. 



In order to determine if the white pine weevil can live and breed on 

 pitch pine and red pine, four leaders from each were placed on June 30, 

 1928, in glass vials eight inches long and one inch in diameter. Two pairs 

 of weevils were liberated in each vial. The vials were inserted in a plas- 

 ter-of-Paris block to provide moisture. 



Jul}' 19, thirteen of the sixteen adults on the four red pine leaders were 

 alive. Larvae were present. Eleven of the weevils placed on pitch pine 

 leaders were alive, and larvae were present in ever}^ leader. 



Later in the season larva; in two of the red pine leaders had died while 

 three and four adults respectively emerged from the remaining two lead- 

 ers about September 6. Five, seven, eight, and seven adults respectively 

 emerged from the four pitch pine leaders about the same date. 



REARING METHODS 



Rearing was carried on in a screened insectary cage with a canvas roof. 

 The floor is of earth. The cage is surrounded by a number of white 

 pine trees and is partially shaded during the day. The temperature is 

 slightly below that to which the insect is exposed under natural condi- 

 tions. Certain phases of the life history work were carried on in a small 

 greenhouse where the temperature was slightly higher than in the field. 



Life historj- data, such as the length of the several developmental 

 stages, were obtained from material in the insectary cage and greenhouse. 

 When possible, observations were checked with field conditions. 



Rearing in the greenhouse and insectary cage was accomplished bj^ us- 

 ing several plaster-of-Paris blocks. Each block is two feet long, six inches 

 wide and four inches high. Twentj'^ or twentj-one holes, one inch 

 in diameter and one-half inch deep, spaced one inch apart, were drilled 

 in the broad upper surface of the block. A one inch hole was drilled 

 from end to end through the central part of the block. A one inch hole 

 drilled in the broad surface near one end connects with the longitudinal 

 central canal. Corks inserted in the ends of the longitudinal canal retain 

 water poured in the connecting hole on the broad surface. 



Eight glass vials, eight inches long and one inch in diameter, each con- 

 taining three or four pairs of adults and a fresh white pine leader, were 

 inserted in the plaster-of-Paris block everj^ day, the open end of the vial 

 in the block. Twenty-four hours later the leaders were removed and 

 fresh ones substituted. The weevils were replaced when necessary. The 

 leaders removed from the vials were examined for eggs under a binocu- 

 lar microscope. Part of the leaders containing eggs were placed in vials 

 inserted in blocks kept in the greenhouse and part in blocks in the insec- 

 tary cage. 



The material was examined daih\ Accurate observations could be 

 made without disturbing the insects. When the larvae advanced to a 

 point where the food supply was endangered a fresh section of a leader 



