1853.] Linnea?i Society. 213 



Read also the commencement of a paper " On the Island and 

 Flora of Hong Kong." By Dr. H. F, Hance. Communicated by 

 B. Seeman, Esq., F.L.S. 



February 15. 



R. Brown, Esq., President, in the Chair. 



Lewis Powell, Esq., M.D., was elected a Fellow. 



Mr. Yarrell, V.P. and 7>eas. L.S., exhibited a specimen of the 

 Sooty Tern (Sterna fuliginosa. Lath.), a species new to Britain and 

 even to Europe, which was killed in October last at Burton -on-Trent, 

 was preserved for, and belongs to the collection of H, W. Desvceux, 

 Esq. 



Read the conclusion of Dr. Hance's paper "On the Island and 

 Flora of Hong Kong." 



Read also an " Additional Note " to Mr. Newport's memoir on 

 Ichneumon Atropos, Curt., in reference to the changes which take 

 place in the alimentary canal after the parasite has ceased to feed, 

 and while assuming its imago state. These changes, which are very 

 considerable both as regards form aud condition, are minutely de- 

 scribed ; and every part of the canal is shown to be supplied with 

 tracheae, the trunks of which, one in each segment, passing trans- 

 versely inwards, divide into branches, which, again subdivided, pe- 

 netrate into and ramiiy through the structure. These, like all other 

 tracheae, are formed, as described by Sprengel, of three tissues, an 

 external membranous and an internal mucous, enclosing between 

 them a strong spiral fibre. The nature and origin of the external 

 tissue have been shown by Mr. Newport in previous memoirs ; but he 

 has since found that the ramifications of the tracheae which pene- 

 trate the structure of the canal, or of any other organ, become de- 

 nuded of this external covering, and then seem to be formed only 

 of two tissues, the spiral and the mucous, if indeed there be not also, 

 as he has some reason to think, an extremely delicate serous, or 

 basement membrane, closely adherent to and uniting the coils of 

 fibrous tissue on its external surface. The ultimate dicisions of the 

 tracheae are always distributed separately, and do not anastomose, 

 ending, as noticed by Mr. Bowerbank, in extremely minute, filiform, 

 blind extremities ; and this Mr. Newport finds to be their condition 



