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



screen. Apples were provided. The sheeting over moist sand 

 afforded moisture. Spaced lath over the top of the cages gave 

 partial shade. In spite of these precautions flies introduced 

 into these cages lived but a few days. 



Ross (55) also found difficult}^ in keeping females alive in 

 confinement under conditions intended to be as nearly normal as 

 possible. 



Illingworth (34, p. 150), by confining the flies in inverted 

 jelly glasses and giving them careful attention, kept some alive 

 for six weeks from the time that they were captured in the open, 

 and others, reared in late summer, to a maximum of fifty days. 



It is certain that in nature individuals live longer than the 

 maximum recorded in our experiments. What the natural 

 maximum may be is not known. 



DISPERSION HABITS OF THE ADULTS. 



The results of many records and field observations through 

 the four seasons of this investigation may be summarized in the 

 following conclusions. 



There is apparently a tendency on the part of the adults of 

 this species to remain in the immediate locality where emergence 

 took ])lace. Although the flies are certainly able to travel 

 considerable distance, there does not seem to be, ordinarily, any 

 marked dispersion instinct at any point in the adult stage, 

 such as exists with many other insects. 



Adults emerging beneath a tree bearing sweet or pleasantly 

 aromatic fruit appear likely to remain in or about that tree. This 

 is true whether the fruit is an early maturing variety, well 

 suited to the life economy of the maggot, or whether it is of late 

 variety, so that actually comparatively few of the larvae hatching 

 in it develop to maturity. 



When the fruit of an early variety has fallen, with adults still 

 in existence about the tree, or when there is failure to fruit, the 

 flies then appear to disperse. If there is another fruiting tree 

 of acceptable variety near they are apt to find it and to concen- 

 trate their attentions on it, though the direction of winds and 

 such matters seem to have an important influence on the manner 

 and direction of dispersion. If the remaining trees near by are 

 not of the preferred varieties there is likely to be scattering 

 infestation, without apparent concentration on anj' one tree, 



