TRANSFERRING THE LARVAE 69 



strong advocates of thirty-six hours as the proper age. Figure 

 27. However, it may safely be said that twenty-four to thirty- 

 six hours is as old as larvae should be for this purpose. Prob- 

 ably up to this age as good or better results will be obtained as 

 from the use of younger ones. 



Something has already been said about the importance 

 of selecting the breeding stock carefully. This is a vital mat- 

 ter if good results are to come from the breeder's work. The 

 larvae used in grafting should be the product of the best queen 

 available. 



At Figure 27 we show the magnified larvae in the cells 

 at about the proper age for grafting. Sladen recommends 

 that larvae not quite as large as a lettuce seed be used. With 

 a little experience one will soon come to tell readily the ap- 

 proximate age of the larvae by the appearance. 



