92 



give it the appearance of being covered with cotton wool. This 

 makes them more conspicuous than most insects of this group. 

 They cause great damage to the trees at times. Kerosene or other 

 emulsions washed over the tree would be useful. Dr. Riley says, 

 " I haye experimentally found that a washing with a weak solu- 

 tion of cresylic acid soap will kill them instantly." Lace winged 

 flies and doubtless other insects eat them freely. Another species 

 which is quite common is one which produces very conspicuous 

 and easily recognized galls on the upper side of the leaves ; this is 

 the 



COCKSCOMB GALL LOUSE. 



Colopha uhnicola^ Fitch. 



The general condition ot leaves infested by this insect is shown 

 in figure ^'o a. though, of course, there may be more or less of 



Figure 66. 



Cockscomb Gall Louse. 

 Colopha ulniicola. 

 a. Leaf with galls; b. egg with dried skin of parent; c. young louse; (/.pupa of c. 

 e. perfect, winged insect oi c; f. antenna of e. ; g. antenna of first brood ; h. an- 

 tenna of c. All enlarged. 



