68 HUMBLE caEATtJRES. 



" The parent Hy laya her eggs four times 

 during the summer, and each time she 



deposits 8(J eggs, making 320 flies. 



Now, it must be assumed that half of these 

 are females, so that at each of the four 

 depositions 40 females are bom : — 



(1) The first eighth, or the 40 females re- 



sulting from the first deposition, lay 

 again four times during the season, 

 making together 12,800 „ 



Again, the first eighth of these, or 1600 

 females, deposit three times, making . 384,000 „ 



The second eighth, or 1600 females, de- 

 posit twice, making 256,000 „ 



The third and fourth eighths, or 3200, 



deposit once, making 256,000 „ 



(2) The second eighth, or 40 females of the 



first deposition, lay three times more, 



making 9,600 „ 



One-sixth of these, or 1600 females, de- 

 posit again three times, making . . 384,000 „ 

 The second one-sixth, or 1600 females, 

 deposit again twice, making . . . 256,000 „ 



The third one-sixth, or 1600 females, 



deposit again once, making .... 128,000 „ 



(3) The third eighth of the first laying, or 



40 females, lay twice, making . . . 6,400 „ 



Of these, one-fourth, or 1600 females, 

 deposit twice, making 256,000 „ 



(4) The fourth one-eighth of the first depo- 



sition, say 40 females, deposit once 



more, making 3,200 „ 



Whereof one-half, say 1600 females, de- 

 posit at least once, making .... 128,000 „ 



*Total. . . 2,080,320 flies." 



* Keller makes the addition 2,208,420, which appears erro- 

 neous ; but for our purpose it is immaterial. Another natmralist 



