McCracken, Egg-layirjg Apparatus of Silkworm. 277 



C issued Sept. 4, a. m., mated Sept. 4, p. m. 4, decapitated Sept. 5, p. m., 1.30. 

 Time rate of ovipositing after stimulation. 



1st group, Sept 9, 11.35—7,5,11, 14,6,7,6,4,5,4,4,5,9,5,6, 16,5, 6, 6,6,5, 



5. 5. 6, 5, 5, 4, 4, 5. 6, 5. 4, 9. 7. 4, 9. 4, 29, i . Total, 34 eggs, i per sec. 



2d group, Sept. 9, 1 1.45— 2, 3, 3, 4, 5, 14, 5. 7» 7. 4, 4, 5. 4, 6, 5, 4, 5, 5, 3, 3, 4, 5. 

 6, 8, 5, 4, 5, 5, 15, 6, 7, 8, 9, 6, 5, 6, 5, 8, 54, 5, 5, 5, 5, 6, 6, 1 1, 4, 7, 3, 3, 3, 4, 5- 5' 

 4,4,10,3,3,10,5,6. Total, 62 eggs. Av., I per 6 sec. 



3d group, Sept. 9, 12 m.— 2,3,3, n, 4, 5, 6, 5, 4, 4, 3, 5, 5. 5» 5> 4, 4, I3» 5. 4, 5, 

 5,5, H, 5,32, 4, 7,5,4, 5- Total, 31 eggs. Av., i per 6 sec. 



4th group, Sept. 9, 12.15— 3, 2, 6, 6, 5, 6, 7, 8, 4, 3, 4, 5, 3, 4, 4, 4, 4, 4, 5, 18, 5, 7, 

 7, 7, 5, 7, 5, 30, 6, 31, 4, 6, 9, 1 1, 5, 6, 36, 5, 8, 8, 7, 6, 18, 18, 57. Total, 44 eggs. 

 Av., I per 9 sec. 



5th group Sept. 9, 12.20—4, 9> i3, 7, 7, 5, 5, 5, 5, 5, 6, 6, 5, 5, 5, 5, 5, 5, 5, 6, 10, 

 3,7, 10,9, 13,8,6, 13,3,10,25,19,11,4,25,3,7,4,6,27,20. Total, 42 eggs. Av., 

 I per sec. 8. 



6th group, Sept. 9, 12.30—3, 4, 23, 26, 1 1, 10, 1 1, 14, 14, 4, 27, 4, 5, 32, 6. Total, 

 15 eggs. Av., I per 13 sec. 



9th group, Sept. II, 4 p. m.— 6, 15, 22, 15, 4, 4, 11, 4, 5, 5, 9, 4, 5, 26, 5, 7, 8 

 (intermittent groups not timed), 4, 9, 7, 5, 6, 5, 4, 6, 29, 4, 7, 6, 5, 6, t,^, 2, 5, 9, i i , 6, 



6, 4, 9, 5, 9, 3, 7, 6, 19, 5, 5, 6, 9, 9, 5, 8, 4, 8, 3, 5, 6, 5, 13, 5. Total, 61 eggs. 

 Av., I per sec. 



loth group, Sept 11, 4.15 p. m.— 4, 13, 14, 7, 55, 57, 31, 44, 51, 16, 4, 7, 28. 

 Total, 13 eggs. Av., I per 26 sec. 



The percentage of the variability fluctuates, it does not progress 

 from day to day as one might expect if one assumed a gradual 

 decrease of tone in the system from day to day. Such an assump- 

 tion appears to be unwarranted with reference to the reproductive 

 system. The following fact lends additional evidence to the 

 unwarrantability of this assumption with reference to the ovi- 

 positor. After the placing of the full quota of eggs, as in Nos. i 

 and 3 in Table IV, stimulation still brings about extension of this 

 organ and normal egg placing movements. In one particular case 

 a moth issued July 10 and produced, after decapitation, and 

 through a series of stimulations, 3 14 eggs in twelve groups, covering 

 a period of seven days. The last eggs were oviposited July 17. 

 Thereafter until July 22, when the moth died, at each stimulation 

 (stimulation was repeated daily) the ovipositor was extended, 

 remaining so for from twenty to twenty-seven seconds before being 

 withdrawn. This was the rule in stimulated, decapitated moths 

 after the ovariole tubes were known to be empty. 



In insects that had been mated previous to decapitation, the 

 eggs were all or nearly all fertile, whether these were oviposited 

 immediately or not for ten or twelve days after decapitation. This 



