THE HEATHER BEETLE 379 



years old and upwards. Most of the damaged heather occurs 

 in patches, and there is a certain amount of evidence that low- 

 lying wet, mossy ground is most subject to attack. This may 

 indeed well be the case, for the beetle requires a good deal of 

 moisture during the period of its metamorphosis from larva 

 to mature insect, and during the course of experiments 

 in artificial breeding of the beetle, it was found that pupae 

 which were allowed to become dry failed to develop 

 properly. 



Taking the whole of the evidence into consideration it would 

 appear that the condition known as " frosted " heather is entirely 

 due to the attacks of the heather beetle. The subject has 

 been further tested by experiment. A patch of heather kept 

 during the winter of 1908-1909 in a warm room was eaten by a 

 number of mature beetles kept in confinement. The condition 

 of the shoots, after being nibbled, was undistinguishable in 

 appearance from some of the samples sent in by correspondents 

 for examination, and in this case frost was, of course, entirely 

 out of the question. This experience is additionally interest- 

 ing as proving that the mature beetle, as well as the grub, 

 feeds upon the leaves. 



The question of remedy alone remains for consideration ; but Eemedy fo 

 this is a matter which presents some difficulty. It is obviously 

 impossible to use any of the ordinary insecticides, as almost any 

 chemical substance sufficiently poisonous to kill the grub or 

 beetle would be dangerous to the Grouse, to say nothing of 

 sheep. The great extent of the area to be dealt with in most 

 cases of attack is also a serious deterrent to the use of spraying 

 mixtures. 



Extensive draining of damp, mossy flats might be indirectly 

 beneficial as a preventative of beetles, and would be directly 

 beneficial to the moor in other respects. But draining is an 

 expensive business, and except in districts where the ground 

 can carry a heavy stock of Grouse, or is valuable for pasture, 

 it may be better policy to allow the low-lying flats to remain 

 in a water-logged condition. 



