ADDITIONS AND COBRECTIONS 



Noctua ditrapezium (Page 58).-The statement that 

 larvae have been found near Rotherham, Yorkshire, proved to 

 be erroneous, 



Aporia cratsegi (Vol. I. p. 18).— The female is described 

 as having " blacker nervures." For Uacker read hrowner. 



Cerura vinula (Vol. III. p. 97).— In my remarks upon 

 the fluid secreted by the pupa and used by the emerging 

 moth to soften its cocoon, I somewhat hastily assumed that 

 the fluid in question is identical with that secreted by the 

 larva in its eversible prothoracic gland. Mr. Oswald H. 

 Latter {Trans. Ent. Soc, London, 1897) has confirmed the 

 previous statement of Professor Poulton that this last— the 

 fluid secreted in the prothoracic gland— is formic acid ; and 

 he goes on to show that this acid is rubbed by the larva upon 

 the silk with which it is forming its cocoon, and has the 

 effect of changing the fibrous character of the silk to the 

 tough, hardened gelatinous material of the ordinary cocoon 

 of this species. 



On the other hand, he proves that the fluid secreted by the 

 pupa, and employed by the emerging moth to assist it in 

 penetrating the hard shell of the cocoon, is of an alkaline 

 character — potassium hydroxide. 



It is not only interesting, but wonderful, to find the 

 creature producing in succession, and without partaking of 

 nourishment during the interval, powerful chemical solvents 

 of so totally opposite a character, from closely adjacent 

 portions of its structure. 



