534 Professor Huxley, on L^^^y 21, 



WEEKLY EVENING MEETING, 

 Friday, May 14. 



TuE Rev. John Barlow, IM.A. F.R.S. Vice-President and 

 Secretary, in the Chair. 



Henry Bradbury, Esq. M.R.I. 

 Printing; its Daiv7i, Day, and Destiny* 



\^No Abstract received. — The Discourse has been printed in full, and a copy 

 presented to the Library of the lloyal Institution.] 



WEEKLY EVENING MEETING, 



Friday, May 21. 



The Duke of Northumberland, K.G. F.R.S. President, 

 in the Chair. 



Thomas H. Huxley, F.R.S. 



rULLKRIAN I'ROFESSOB OF rHTSIOLOGT KOTAL INSTITUTION, AND rROFESSOR OF NATURAL 

 HISTORT, GOVERNMENT SCHOOL OF MINES, JEHMTN STREET. 



On the Phenomena of Gemmation, 



The speaker commenced by stating that a learned French natural- 

 ist, M. Duvau, proposed many years ago, to term the middle of the 

 eighteenth century, " I'Epoque des Pucerons : " and that the im- 

 portance of the phenomena which were first brought to light by the 

 study of these remarkable insects renders the phrase " Epoch of 

 Plant-lice," as applied to this period, far less whimsically inappro- 

 priate than it might at first sight seem to be. 



After a brief sketch of the mode of life of these Plant-lice, or 

 Aphides, as they are technically termed ; of the structure of their 

 singular piercing and sucking mouths ; and of their relations to 

 what are called " Blights ; " the circumstances which have more 

 particularly drawn the attention of naturalists to these insects were 

 fully detailed. 



