188 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



Ridden, and during the last eighteen years he has often cut 

 through their larvre in Scotcli 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 larvae, and did not mistake it for 

 that of some other flv. Sometimes there are large numbers of the 

 larva? 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 throusrhout the island of 

 Bute, durinfj all the vears thev have been workinsr 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. Larvae are invariably obtained in the timber 

 broucrht 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 larvae, and I have pleasure 

 in submitting for your inspection pieces of the wood, along with 

 larvse and insects obtained from it. You will observe how the 

 larvse 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 larvse. 



The insect appears to deposit its eggs with its strong ovipositor 

 in the wood underneath the bark. When the esfi^s are hatched 

 the vouncj larva? bec^in to feed on the wood of the tree, and, in 

 doinjj so, bore these holes throusrh the timber. When the larvse 

 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 larvse 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. 



