66 FIRST REPORT ON ECONOMIC BIOLOGY. 



On the day of collection (first day) the eggs appeared immature. 

 One day later eight eggs opened by picking the operculum off, showed 

 three larvae with slight movement, and five immovable. On the third 

 day a half-hour of friction failed to hatch eggs, but the larvae when 

 freed by picking off the operculum showed two, slight movement ; 

 one, no movement, and one sufficient movement to get out of the 

 opened shell. 



On the fourth day the larvae in eleven eggs were all active, but 

 had to be freed by picking off the operculum ; the same was true up to 

 the seventh day, the only difference being noted in greater maturity 

 and size of larvae. 



On the ninth day, or when the larvae were eight days from deposi- 

 tion, one larva was freed by seventeen minutes' 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 

 probably 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 larvae 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 larvae. On the tw r enty-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 ten eggs, three contained dead 

 larvae, five could move slightly, and two were quite active. On the 

 twenty-sixth day caps were removed from thirty-five eggs, twenty- 

 seven larvae being dead, seven were capable of slight movement, and 

 one was active enough to escape from the shell 



