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DIPTERA. - $1 
On the ninth day, or when the larve were eight days from deposi- 
tion, one larva was freed by seventeen minutes of rubbing with wet 
finger, another in twenty-two minutes; on the tenth day two others, 
one in fourteen and the other in eight minutes; and on the eleventh 
day several were hatched, the time varying from two to five minutes of 
subjection to the saliva and friction. On the twelfth day it required 
but one or two minutes, and on the thirteenth eggs would hatch in 
fifteen to thirty seconds. On the fourteenth day a number of eggs 
were tried, about one-third of which hatched almost immediately upon 
being touched with the moist finger, the others in from five to eight 
seconds. On the fifteenth day all eggs seemed fully mature, and prob- 
ably nine-tenths would have hatched at once upon being touched by a 
horse’s tongue in the ordinary motion of licking. From the sixteenth 
day to the twenty-second the eggs would open with a touch of the 
finger, but the larve would not adhere except with moisture. On the 
twenty-third day the first dead larva was noted, and a day later four 
out of eleven eggs opened had dead larve. On the twenty-fourth day 
all of the eggs not previously opened were examined with a lens, and 
only one showed the cap removed, the larva being partly out, but dead. 
The hatching of but one egg out of three hundred seems to me to 
establish pretty fully my former opinion, that the eggs require moisture 
or friction for the release of the young. 
On the twenty-fifth day, out of 10 eggs three contained dead larve, 
five could move slightly, and two were quite active. On the twenty- 
sixth day caps were removed from thirty-five eggs, twenty-seven larve 
being dead, seven were capable of slight movement, and one was active 
enough to escape from the shell. 
On the twenty-seventh day out of forty-three eggs opened only one 
larva was alive, and on the twenty-eighth day only one out of sixty-five, 
and on the twenty-ninth day all the remaining eggs, one hundred and 
three, showed only dead larve. 
The results of this study, it will be seen, confirm in the main the con- 
clusion of the former observations, the principal difference lying in the 
fact that all the larve were dead at a somewhat earlier period. Of 
course it could not be said that of the eggs opened in the earlier days 
none would have survived longer than four weeks, but considering the 
number used and that one-third of them were kept the full four weeks 
and two-thirds nearly that long before being opened, the presumption 
is strong that that is the full normal period of survival. 
It is safe, I think, to sum up the matter by. saying that the eggs nor- 
mally require friction and moisture to permit of their hatching and trans- 
fer to the horse’s mouth, that hatching occurs with diffienlty before 
the tenth day, and most readily after the fourteenth day, and that they 
lose vitality at a period varying between the twenty-eighth and fortieth 
days, the bulk not surviving more than four weeks. This.gives a solid 
foundation upon which to base recommendations as to the time when 
eggs must be destroyed. 
4653—No. 5 6 
