176 A Parasite o^i the Pine Weevil 



ten, and that the proportion of males to females in the two insects is the 

 same, then we should have in the winter 1914-15, 420 weevil grubs and 

 540 Braconid. This would, therefore, entail the complete destruction 

 of the weevil. These figures are of course purely hypothetical. Now 

 it is by no means improbable that the Braconid is more prolific than 

 the weevil, and also that the proportion of females to males in the Bra- 

 conid is greater than in the weevil. These, however, are points which 

 must be cleared up before the practical value of Bracon hylohii as a 

 factor in controlling Hylohius can be fully demonstrated. 



