1899-1900.] Dr E. Stewart MacDougall on Genus Pissodes. 349 
Pine 1. 
On 13th July 1896 I surrounded a healthy seven-year-old young 
Pinus sylvestris , which Was potted, with muslin as in the notatus 
experiments, and seventeen piniphilus having been introduced, the 
pine was placed outside. On examination of this pine on 8th October 
the piniphilus were found alive, and were removed. In the 
summer of 1897 I dissected this pine from top to bottom. The 
pine was still alive and healthy, and had made some growth during 
1897 in spite of its having been surrounded all the time with a 
muslin bag. Here and there over the pine were the proboscis 
punctures made in the previous year by the feeding piniphilus, and 
on the bark being stripped the brown discoloured spots here and 
there on the alburnum attested the feeding. There was no trace,, 
however, of eggs having been laid. 
Pine log 2. 
On 14th July 1896 another pine log was paraffined and placed 
in a sack. Between 14th July and 25th July twelve piniphilus 
were introduced, and allowed to remain till 3rd October. Here, 
again, I could find no trace of any egg-laying. 
Pine 2. 
On 12th October 1896 I surrounded another potted pine with a 
muslin covering and introduced thirteen piniphilus, all of them 
from the brood obtained in July. As this pine was larger than 
those usually employed, and the muslin sack presented too great a 
surface to safely allow the pine to be exposed to a high wind, the 
pot was sunk in the soil in a little glass-house at the Eoyal Botanic 
Garden. The door of this house was always left open, and except 
for the protection of the surrounding glass, which was broken in 
many places, the weather conditions were the same as outside. 
One can safely believe that no eggs were laid in October or before 
the next year. In the soil of the pot and under the moss provided 
for the purpose these piniphilus hibernated during the winter of 
1896-97. On looking over the pine on 2nd April 1897 I noticed 
