52 N. H. AGR. EXPERIMENT STATION. [Bulletin 171 



Field Observations. In field observations flies have repeatedly 

 been observed well into September. On September 9 many flies 

 were noted in and about a Tolman Sweet tree. Other similar 

 observations were made. 



No difl&eulty was experienced September 5 and 7, 1911, in 

 finding females engaged in egg-laying. The process was watched, 

 the eggs marked, and larvae hatched from the eggs. 



Harvey (25, p. 206) states that in Maine egg-laying continues 

 until the flies die in the fall by kiUing frosts. Females taken by 

 him about the middle of September were dissected, and were 

 found to contain eggs in varying stages of development. 



EGG-LAYING PERIOD OF INDIVIDUAL FEMALES. 



Efforts to maintain individual females under observation 

 throughout the entire length of their normal egg-laying period 

 were unavailing. Definite data were not secured on this point. 



Harvey (25, p. 207) dissected the female genitalia, and from 

 the number of eggs and the developmental stages concluded 

 that egg-laying must extend over a considerable time. Illing- 

 worth (34, p. 143) made careful dissections, tracing the develop- 

 ment of the egg, and concluded that flies are able to continue 

 ovipositing during the remainder of their active existence, after 

 egg-laying is once begun. 



Egg-Laying in Fallen Fruit. In no case were flies ever ob- 

 served laying eggs in apples that had dropped from the tree. 

 In normal surroundings flies were never seen on or near the 

 ground, except at the time when they were emerging. 



LENGTH OF LIFE OF THE FEMALE. 



The longest period during which an individual female was 

 kept alive in confinement was thirty-three days. This was in 

 1913, in rearing cages set up in the open-air insectary. The 

 type of cage and the manner in which the flies were handled has 

 been described in the discussion of experiments of that year to 

 determine the length of the period after emergence before egg- 

 laying. The detailed results are given in Table 6. No method 

 was discovered by which flies could be kept alive in natural 

 surroundings for a period that could be assumed to equal the 

 maxinumi or even the normal. 



