NOTES ON SILK-PRODUCING BOMBYCES. 127 



characters in this insect ? It is quite as distinct from typical 

 corydon as typical lujlas or eros are from icariis. Is there any 

 fixed rule to guide us in determining the exact point at which a 

 variety merges into a species ? I am not aware of any such rule. 

 In fact I doubt if any set of rules could be framed which would 

 meet the requirements of all cases. I agree with those who 

 consider an aberration as the first stage, as it were, in the 

 development of a species ; but I hold the opinion that a local 

 form, however greatly it may have become modified from the 

 type, cannot legitimately rank as a species, whilst individuals 

 occurring among either the local or type forms can be found to 

 connect the two. 



In conclusion, I may say that I regret being unable (from 

 want of material) to enter into a consideration of some other 

 species and forms of this most interesting but perplexing genus. 

 I can only hope that at some future time, when I may have 

 extended my series of certain species and obtained some local 

 forms, I shall be able to add a few further notes on the 

 genus Lyccena. 



NOTES ON SILK-PRODUCING BOMBYCES— 1885. 



By Alfred Wailly. 

 (Membre-Laur^at de la Societe d'Acclimatation de France.) 



In my previous reports on the rearings of wild Silkworms 

 and other exotic Lepidoptera, I have invariably spoken of the 

 cold weather, or sudden changes in the temperature, as one of the 

 two great impediments in the way of their successful rearing in 

 the open air or indoors at the ordinary temperature. In 1885 

 the weather was even more unfavourable than in previous years. 

 The months of May and June were so cold that tlie emergence of 

 moths from the cocoons was delayed several weeks, which 

 created such a disturbance in the economy of the insects that 

 many of the eggs obtained were infertile. Cocoons, such as 

 tliose of Attacus atlas (Ceylon race), all died, and out of a large 

 number of Cricula trifenestrata only three moths emerged. 

 British Lepidoptera were affected in a similar manner, although 

 not so much as exotic species. I shall therefore, in future, keep 

 the cocoons at a '^arm and even temperature from the beginning 



