Edward R. Speyer 



175 



about ten days, the second stage lasts from 3-6 days, the third from 

 5-9 days, and oviposition about ten days. 



The fact that wax-wool is secreted by third-stage larvae, two days 

 after the second moult, may possibly have led Mr Steven to believe that 

 only two moults altogether occur in the later Progrediens generations; 

 at any rate, the matter is one of little importance, and can easily be 

 cleared up. 



in. STATISTICS OF THE COLONICI GENERATIONS. 



A. SiSTENTES. 



The Sistens larvae all hibernate in the first stage, only becoming 

 adult in the spring following; as found in nature, they have a triple 

 origin : 



(1) From eggs laid by the Gallicola migrans. 



(2) From eggs laid by the first generation of Sistens derived from (1). 



(3) From eggs laid by the Progredientes of several generations. 



In February, 1914, adult Sistentes were observed on Larch in Hert- 

 fordshire, and the eggs laid by them collected, to determine the propor- 

 tion of Progrediens and Sistens larvae hatching from them. 



During these observations a few of the egg-clusters were kept in a 

 warmed slass-house, the rest outside; in both cases there was a total 



