16 



BULLETIN 431, U. S. DEPARTMENT OF AGRICULTURE. 



amount of sacbrood is readily produced, showing that the larval re- 

 mains in this stage are particularly infectious. This is an important 

 fact, as it is the stage of decay at which the larva is frequently re- 

 moved piecemeal from the cell. 



Second Stage. 



The color of the decaying larva has changed from the yellowish hue 

 of the first stage to a brownish tint. The yellow, however, has not 



Fig. 17.— Third stage: Dorsal view of an- 

 terior third of larva dead of sacbrood. 

 (Original.) 



yet in all cases entirely disappeared. 

 Anterior third. — The shade of 

 brown is deeper in the anterior third 

 (fig. 15; PI. II, i) as a rule than in the 

 other two thirds. On the ventral 

 surface of the anterior third there are 

 sometimes present minute, very 

 dark, nearly black areas, appearing 

 little more than mere points. Upon 

 dissecting away the molt skin, these 

 areas are found to be associated with the developing head and thoracic 

 appendages of the bee. The position of the anterior third in this 

 stage has changed only slightly from that observed in the preceding 

 one. The apex is farther from the roof of the cell (PI. II, i). The 

 deflection is more marked and is seen hi a greater number of larvae. 

 The surface markings have not changed materially. 



Middle and posterior thirds. — The changes that have occurred in 

 each of these two thirds are still similar and can, therefore, again be 

 described together. 



Fig. 16. — Second stage: Larva dead of sacbrood 

 ventral view. (Original.) 



