6 PROCEEDINGS OF THE ACADEMY OF [Jan., 



The lice within the galls are light red in color, and their bodies are 

 more or less covered with the white waxy secretion which occurs both 

 in the form of a powder and as threads. It might seem that there 

 would be no need of this secretion as a protection in the galls, but it is 

 of the greatest importance here as the lice give off a large amount of 

 liquid excretion, which would drown them if it was not prevented from 

 touching their bodies by their covering which is not wet by the excre- 

 tion. The cast skins also come into service here. Prof. Cooley has 

 called attention to the fact that the lice within the galls of Chermes 

 abietis retain their cast skins for a time, fastened to the posterior end of 

 the body. If one of the galls is broken open when nearly mature, the 

 cast skins may be seen filled as full as they can hold with the liquid 

 excretions. Thc,y may be shaken out in the hand and examined, but 

 are easily broken. Thej^ appear like plump white models (ghosts) of 

 the lice that shed them. 



About the 1st of July at Fort Collins the lice begin to transform to 

 pupse, and a few days later the most advanced galls begin to open. 

 The earliest gall found with lice escaping in 1906 was taken by Mr. L. C. 

 Bragg, July 3, on a tree exposed to the open sun on the south side of a 

 building. On Juh' 16, trees most exposed to the sun and not very 

 thrifty had matured nearly all their galls and most of the lice had 

 escaped. Large, more thrifty trees, and especially those that were 

 shaded much of the time, still had most of their galls closed, and par- 

 ticularly upon branches near the ground. Galls broken open at this 

 time expose the pupte, which seem to pack every chamber full, and all 

 their heads point outward from the centre toward the place of exit, 

 ready to escape once more into the light of day as soon as the opening 

 is made large enough. The pupce cling to nearby leaves, usually those 

 of the gall, and shed their skins. During the few hours that the lice 

 stay upon the leaves the little white patches of cottony secretion begin 

 to show like masses of mycelial threads of a fungus. 



After a few hours of resting upon the galls the winged lice all leave 

 and go, so far as I have been able to trace them, to the red fir {Pseudo- 

 tsuga mucronata), where they settle upon the leaves, insert their beaks, 

 and begin almost immediately to lay eggs, which accumulate in large 

 piles beneath their wings. Each egg is anchored by a short silken 

 thread attached to one end. The threads vary in length from those 

 that are shorter than an egg to those that are more than twice that 

 length. The threads also cling to the eggs and to one another after 

 they are loosened from the leaf, so it is very difficult to separate them 

 out from the"general cluster (see PI. IV, figs. B and D). The white 



