256 MAINE AGRICULTURAL EXPERIMENT STATION. I915. 



time the larva is half grown, the fruit becomes much shrivelea 

 and shrunken. This condition is illustrated in figure 60 A. In 

 every case which the writer has observed at all closely the larva 

 has attained its full growth in one berry, which it leaves by an 

 irregular and jagged exit-hole. Nor has he ever found more 

 than one larva per berry under natural conditions. Usually the 

 fruit falls off shortly before the larva becomes full-fed, but at 

 times it may remain on the bush after the maggot has entered the 

 soil. In such cases the larva doubtless works its way to the 

 surface of the berry and then drops to the ground. 



The Pupa. When ready to form their puparia, the larvae 

 enter the soil which is of a sandy character on the barrens, but 

 probably do not penetrate to a depth of much more than an inch. 

 Under laboratory conditions they barely bury themselves be- 

 neath the surface in most cases. As is characteristic of this 

 group of flies, pupation takes place within the last larval skin 

 which is not molted but shrinks up and hardens, turning a light 

 yellowish brown. Invariably the -puparia are formed within 2 

 days after leaving the berry and usually within one. Transfor- 

 mation to the pupa takes place within 7 days after the puparia 

 have been formed, usually about the fifth day. 



The earliest date on which the waiter obtained puparia In 

 1914 was on August 21, which would indicate that the first eggs 

 •were deposited about August 5. As has been stated previously, 

 29 puparia were found on August 22, 19 13, in material collected 

 on July 30, but, as has been explained, the difference in the cli- 

 matic conditions easily accounts for the apparent discrepancy 

 of the records. 



Below is given in tabulated form the dates on which the 

 writer removed full grown maggots which had left the berries, 

 and puparia from the breeding cages, in 1913, 1914 and 191 5. 

 All material was collected in Cherryfield, Maine. 



