Ailanthiculture. 207 
It seems, therefore, that the number of eggs to the weight of 
1 grain varied from forty to twenty-seven (compare M. de Roo’s 
calculation, ante, p. 191). I think this is to be explained in the 
following way ; the first moths that emerged were much smaller, 
and laid fewer eggs than those produced later in the season; their 
eggs, too, were certainly not so large as those laid afterwards; a 
larger proportion of larvz also were observed to hatch out of the 
eggs laid later in the season. It would seem, therefore, that in 
selling eggs by weight, the finer and larger the brood the fewer 
they would be, while the more numerous the eggs the greater pro- 
portion would be lost before attaining perfection. I think most 
people would prefer having the smaller number but the finer eggs. 
As to the number of eggs laid by a single female, I have the 
following observations: one @ of the second brood in 186% 
emerged 26th August, coition took place that night, and by Sep- 
tember 3rd she had laid 262 eggs in all. 
1864. July 4th—9th .. 1 @ laid 185 eggs. 
14th ee FL MOG) F208 
21st a SY ye 290 
Oct. 29th—Nov. 8th 1 9 ,, 246 
Eggs. Average. 
1865. May 24th .. 1 9 laid 102. 108 
July 7th—15th 42 ,, 938 .. 2344 
10th—21st 42 ,, 835 .. 209 
Aug. 24th .. 1 Ss 59) 288 act) ae 
be Sy tll | x LS eens 
It would therefore seem that the number of eggs laid by indi- 
vidual females varies from 100 to 300 and upwards, and that the 
earlier in the season the insect appears the fewer the eggs laid. 
It would, perhaps, be a safe calculation to expect from 150 eggs 
to 200 from each female. 
The number of males generally preponderates over that of the 
females ; as, for instance, out of 104 cocoons in 1865 set apart for 
obtaining a second brood, by Sept. 2nd there had emerged thirty- 
nine females, forty-six males; from these thirty-five pairs were 
obtained. Subsequently nine females and six males were born 
between Sept. 3rd and 21st; from these but one pair was ob- 
tained, one cripple emerged, and two or three cocoons did not 
produce anything. From these 36 pairs 8,438 eggs were ob- 
tained, giving to each fertile 6 an average of 235 eggs, or about 
83 eggs to each cocoon. The males generally proponderate at 
the beginning, the females towards the end of the time of exit. It 
will therefore be impossible to obtain fertile pairs from all that 
