WILD SILKWORMS. 99 



morphoses. But there are many difficulties in the way of success. 

 Our climate is so variable, that while one season may be 

 exceptionally fine and therefore yield most encouraging success, 

 the next may turn out just as wet, and prove in consequence, 

 most disastrous. In the transmission of cocoons to this country, 

 especially from the east of Asia, great risks to the life of the 

 insect are run, and large numbers perish in one way or other on 

 the journey, so that, unless an abundant supply can be secured, 

 success is likely to be but trifling. 



A few figures from the experience of M. Wailly will well 

 illustrate this. At the end of February 1880 he received from 

 Calcutta nine hundred cocoons of the Tusser Moth ; on their 

 arrival, he found that seven hundred and fifty of them had died 

 during the passage; out of the nine hundred, therefore, only 

 a hundred and fifty remained for him to rest his hopes upon. 

 In the middle of April, in the same year, he received another 

 consignment of only a hundred cocoons, packed in a tin box. 

 A totally different disaster had happened to these : the season 

 being now so much more advanced, and the heat having been 

 great on the journey, the natural time of hatching had been 

 anticipated, and more than two-thirds of the moths had emerged 

 during .the voyage, and in the confinement of the box had of 

 course ruined themselves. A similar fate befell one hundred and 

 eleven cocoons of the gigantic Atlas Moth received from India on 

 another occasion. On opening the box, the consignee was 

 chagrined to find it full of broken wings and dust ; the great 

 creatures had made their exit from the cocoons during trans- 

 mission, and had knocked themselves to pieces. 



And even if they do travel safely, reach their destination alive, 

 and issue in due course as moths, it by no means follows that 

 eggs will be obtained such as shall be suitable for propagating 

 the race. The moths may issue at irregular intervals, either 

 singly, or with perhaps several of one sex only at a time, so that, 

 as they rarely live many days after acquiring their adult form, 

 those first out may die before there is any chance for them to 

 get mated. For example, M. Wailly had once sixty cocoons of 

 A. Selene from which he only obtained one pairing, because the 

 moths emerged at intervals from March to August, and when a 

 number did happen to issue near together, they perversely turned 

 out to be all of the same sex. 



The time of issue of the moths, too, is very irregular when they 

 are removed from their native climate, and M. Wailly has found 

 that " tropical species are apt to emerge during the winter when 

 the weather is mild, while moths of native, or northern foreign 



