188 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 
Ridden, and during the last eighteen years he has often cut 
through their larve in Scotch Fir grown in Bute, and sent to the 
sawmill by the Bute Estate people to be cut up for themselves. 
He is quite conversant with the larve, and did not mistake it for 
that of some other fly. Sometimes there are large numbers of the 
larve in the wood, so much so that the saws become “greasy ” 
when cutting through them. At other times they are fewer in 
number, but nearly every season they notice some of them. 
Several of the foresters and woodmen say they have often seen 
the fly, sometimes two or three together, flying about or resting 
on the timber in various of the woods throughout the island of 
Bute, during all the years they have been working in them. 
Walter Swan, who has been employed as wood foreman in 
Arran for the last twelve years, says he has often seen the fly in 
Merkland Wood, near Brodick Castle, Arran —frequently two 
or three at a time, and single ones so often that he paid little 
attention to them. Larve are invariably obtained in the timber 
brought to the mill from this wood. 
It would therefore appear, that for many years this fly has been 
observed regularly in Bute and Arran, and also in wood at 
Ormidale, Argyllshire. 
Early in May of the present year, while some Scotch Fir from 
Merkland Wood, Arran, was being cut in the sawmill, one tree 
was found to contain a large number of larvee, and I have pleasure 
in submitting for your inspection pieces of the wood, along with 
larve and insects obtained from it. You will observe how the 
larve have filled up their borings, as they proceeded, with the 
refuse from the wood. This refuse is packed quite hard in the 
tunnels by the larve. 
The insect appears to deposit its eggs with its strong ovipositor 
in the wood underneath the bark. When the eggs are hatched 
the young larve begin to feed on the wood of the tree, and, in 
doing so, bore these holes through the timber. When the larve 
are present in large numbers in the trees, the wood may be so 
riddled by their borings as to make it quite useless for any 
purpose but firewood. The local trees, however, have never been 
found wholly damaged to this extent. The larve are of a creamy- 
white colour, but are inclined to turn black when preserved in 
methylated spirits, as you will notice from the specimens shown. 
