174 A Parasite on the Pine Weevil 



The degree of parasitism by B. hylobii on the pine weevil may be of 

 interest. In winter 1911 I observed no cocoons. In the spring of 1912, 

 two years after the old crop was removed and presumably in the second 

 year of the beetles' occurrence there, I observed a few cocoons, while in 

 1913 and 1914 every third pupating chamber was occupied by them. 

 This represents parasitism in the third and fourth years of the pest of 

 over 30 per cent, 



I think I do not exaggerate when I suggest that Bracon hylohii 

 Ratz. may prove of considerable value in combating the pine weevil, 

 which is every year becoming more and more common in newly formed 



Fig. 4. B. hylobii ? . x 15. . 



plantations, es])ecially in Scotland. The parasite is, in all probability, 

 fairly common where Hylohius is found. The fact that it has hitherto 

 apparently been unrecorded does not imply that it is scarce. The 

 persons most interested in Hylohius, the forester and the factor, are 

 interested only in the adult beetle when it begins its attacks on their 

 plantations, and any measures they may take against it arc as a rule 

 confined to the trapping and collecting of the adult. The larvae are 

 rarely considered, and though they were disturbed and examined, the 

 forester is neither sufficiently interested nor sufficiently educated to 

 pay any attention to the cocoons, or larvae of a parasite, though he 

 found them. 



