156 Journal New York Entomological Society. [^'°1- xxviil 



served. The hundreds of larvae seen were practically all the same 

 size, no small specimens being observed. The larvae do not work in 

 the cambium but go directly into the wood. 



The mines, Plate VIII, figs, i and 2, are flat, approximately 4 by 

 1.5 mm. in cross section, very long, winding, often crossing each 

 other. Before pupation the larva excavates almost to the surface 

 then retreats back into the wood, enlarges the mine and pupates. 

 When ready to pupate the larva is always found doubled back on 

 itself with the head and anal end pressed tightly together. The newly 

 formed adult makes its way to the surface along the mine made by the 

 larva. This flat mine is too small to allow the passage of the body 

 of the adult, so it is forced to enlarge it, emerging through a perfectly 

 round tunnel from 3.5 to 4 mm. in diameter. 



Work. 



The flat mines of the larva literally honey-comb the wood of 

 trees attacked. 



A Grand fir tree, sixteen inches in diameter, was found attacked 

 from the base to a height of eight feet and there was hardly a square 

 inch of the wood which was not penetrated by at least one mine. This 

 tree was living when first noted (1914) and the colony of beetles had 

 been in it for some time as there were numbers of emergence holes 

 present. In 1916 the tree broke off at a point four and one-half feet 

 from the ground ; there were still many beetles present in various 

 stages. The tree was still living but so weakened by the larval mines 

 that it was an ea^y prey to the wind. The only other colony of these 

 beetles observed was in a white fir and the tree had been broken off 

 by the wind in the same manner. A few dead beetles and the char- 

 acteristic mines gave evidence of the cause. 



Distribution: Washington, Oregon and Nevada. In Oregon a 

 few dead specimens were collected on Paddy Creek near Sparta, in 

 the Blue Mountains of Grant County, and a large colony lived for 

 years in a Grand fir tree within a mile of the Oregon Experiment 

 Station at Corvallis. 



Hosts: Taken from Grand fir (Abies graiidis) and white fir (Abies 

 concolor) . 



