118 INJURIOUS INSECTS OF 1909 AND IQIO. 
METHOD OF REARING BORERS. 
As it became desirable to rear borers from white birch, a means 
was devised for doing so by Dr. Franklin, at that time in charge of 
the Insectary; and it proved so satisfactory that it seems worth 
while to describe it. This method has served not only the pur- 
pose of rearing these borers, to find out what they are, but it has 
proved to be so effective that it has value in rearing all borers when 
present in large numbers; and probably, by means of this method, 
a practically complete emergence can be obtained, thus giving a 
good idea of the amount of infestation in all cases in which this 
method is used. 
Fig. 69. A device for rearing borers from a log of considerable size. 
Inclosing the log. Franklin. 
A portion of a cut-leaf birch log, badly infested with larvae of 
the Bronze Birch Borer, Agrilus anxius, seven and one-half inches 
in diameter at one end, and six inches at the other, and four feet 
two and one-half inches long, was carefully and loosely wrapped 
