THE SILKWORM ITS REARING AND MANAGEMENT. 63 



to this point ; how then are we to tell which cocoons will produce 

 male moths, and which females? It has been generally supposed 

 that the male cocoons are smaller and less rounded at the ends than 

 the females ; but though it is no doubt generally true that the largest 

 cocoons will produce females, it is impossible to be absolutely 

 certain, and therefore rather more should be saved than are theo- 

 retically necessary, in case the educator's discrimination should have 

 been much at fault. The magnitude of the projected breeding of 

 the next year will of course determine how many insects' lives are 

 to be spared. Reckoning that each female will produce about 

 three hundred eggs, we should require, for example, if an "educa- 

 tion ' : of thirty thousand be projected, two hundred moths, halt 

 females and half males. Therefore some two hundred and twenty 

 or two hundred and thirty cocoons ought to be saved ; and for 

 smaller numbers in the same proportion. The best for breeding 

 purposes are not necessarily the largest, but those that are the 

 firmest to the touch and the most delicately coloured, except in 

 the case of the green cocoons, when the greener they are the 

 better. If there are any double or treble cocoons, these may be 

 used for breeding pur- 

 poses, though they will 

 be useless for reeling. 



The breeding cocoons 

 are pasted close together, 

 side by side, on sheets of 

 cardboard, in rows which 

 are at the distance of a 

 little less than a moth's 

 length from one another 

 (Fig. 19). The card- 

 board is then placed in 

 an inclined position so 

 that each moth as it 

 comes out may easily find 

 a resting-place on the 

 cocoon immediately above it, and cling to it in a suitable posi- 

 tion to dry its wings. Another method of arranging them is to 

 thread them on a string like birds' eggs, taking care, however, 

 on inserting the needle, to pass it only through the silken cover- 

 ing, and not to injure the chrysalis within. The strings may then 

 be hung up like strings of onions. The male and female cocoons 

 should be put, as far a-s possible, on different sheets of cardboard, 

 an attempt at their separation being made as above, or by weighing 

 the whole lot so as to calculate the average weight of a single 



ifiiininj 



Fig. 19. 



