THE CRANBERRY GIRDLER. 11 



Table IV. — Cocooning records of the cranberry girdler in New Jersey, 1915. 



Date. 



Number 

 of larvae in 

 cocoons. 



Number 



of naked 



larvse. 



Date. 



Number 



of larvae in 



cocoons. 



Number 



of naked 



larvae. 



Sept. 8 





 

 

 3 

 



21 

 15 



7 



17 

 2 



Oct. 5 



9 

 6 



37 

 1 



26 



1 



Sept. 14 



Oct. 11 



1 



Sept. 19 



Oct. 15 



1 



Oct. 1 



Oct. 19 







Oct. 4 



Nov. 17 













The foregoing figures, obtained under actual bog conditions, show 

 that cocoons were first found October 1, although search was not 

 made for them between September 19 and that date. Naked larvse 

 were abundant on October 1, but this condition soon changed, and 

 by the 5th of October larvse in cocoons outnumbered the naked ones. 



After making the cocoon, the larva lies dormant within until 

 spring of the following year, at which time pupation occurs. Larvse 

 in cocoons are able successfully to withstand the usual winter flow- 

 age, which is applied, as a rule, in December and held until the fol- 

 lowing April or May. Some few are able to withstand a flow age 

 lasting until July, although an infestation is always greatly reduced 

 by such late holding. 



The cocoon is not impervious to water and, in fact, becomes filled 

 with water about three days after submergence. After 24 hours' 

 submergence in a solution tinged with red, the inner wall of the 

 cocoon was found entirely reddened, with no free water around the 

 larvse. Similar results were obtained with another cocoon after 48 

 hours' submergence, while at the end of four days three cocoons were 

 entirely filled with the solution. 



PUPA STAGE. 



Pupation occurs after the removal of the winter flowage and is de- 

 pendent upon the time of this removal. On dry bogs it may occur 

 in late April or May, and on winter-flowed bogs it may be retarded 

 by late holding of the flowage until July. No evidence has been 

 noted of pupation taking place while the winter flowage was on; 

 in fact, the examination of cocoons within a day or two after the 

 drawing of the winter flowage showed all such to contain larvse. 



After pupation has occurred the bog may be reflowed for several 

 days without effecting the death of the pupa. On one occasion a 

 pupa in its cocoon was found alive on the bog after submergence for 

 between five and six days. 



Pupal records have been difficult to obtain, because the opening 

 of the cocoon for purposes of observation is disturbing to the larva 

 and is likely to result either in its death or in delaying its transfor- 

 mation to the pupa. The records at hand show that the stage lasts, 



