SACBEOOD. 



19 



are not infectious. The status of the virus in this stage is not defi- 

 nitely known, but the facts thus far obtained indicate that it is 



probably dead. 



Fourth Stage. 



The brown color of the larval remains has further deepened, the 

 anterior third being much darker as a rule than the other two-thirds. 

 The marked evidence of drying now present might be said to charac- 

 terize this stage. 



Anterior third. — The color is a very deep brown, often appearing 

 almost black. As a result of drying, the apex of this coneHke third 



Fig. 20.— Fourth stage: Remains of larva 

 dead of sacbrood. (Original.) 



is often nearer the roof of the cell in 

 this stage than in the preceding one. 

 As a result it has also been drawn 

 inward from the mouth of the cell. 

 The surface markings seen in tbe 

 normal larva are in this stage (fig. 

 20 ; PI. II, 1c) of decay almost obhter- 

 ated tlu-ough the wrinkling of the 

 surface, duo to dr}'ing. 



Middle third. — This third is de- 

 cidedly brown, but light<!r in shade 

 than the anterior third. The ventral surface (fig. 21; PI. II, q) is 

 slightly conclave from sid<^ to side. The segmental markings are stiU 

 to be seen, Imt arc not at all promincait. The notched lateral mar- 

 gins extend upon the side walls of the cell. The subcuticular fluid 

 so noticeable in some of the earlier stag<'3 has disappeared through 

 cva])()ralioii. Tlie effect of drying is very i)oticeHl)le, causing a 

 marked wrinkling of the surface. 



Posterior third. — The y)osterior third (PI. 11, q) may or may not 1)(^ 

 darker than the middl(! liiiid, but it is not darker than the anterior 



Fig. 21.— Fourth stage: Remains of larva dead 

 of sacbrood, ventral view. (Original.) 



