4 CIRCULAR 3 9 2, U. S. DEPARTME17T OF AGRICULTURE 



Figure 2. — American foulbroofl : A, Healthy brood In new brood comb ; B, old brood comb 

 with an advanced case of American foulbrood ; 0, scales of larvae dead of American 

 foulbrood on a cross section of a new comb ; D, scales of larvae dead of American foul- 

 brood in an old brood comb. 



