1920] General Monthly Meeting 131 



Sanitary Institute, Eoyal— Journal, Vol. XL. No. 4. 8vo. 1920. 

 Smithsonian Institution — Miscellaneous Collections, Vol. LXIX. No. 1; Vol. 



LXXI. Nos. 2-5. 1918-20. 8vo. 

 Societd degli Spettroscopisti Italiani — Memorie, Serie 2, Vol. VIII. Disp. 7-8. 



4to. 1919. 

 South Africa, Union of, Department of Agriculture — Bulletin, 1919, Nos. 7-8; 



1920, No. 2. 8vo. 

 Swiss Chemical Society — Helvetica Chimica Acta, Vol. II. Fasc. 2. 8vo. 1920. 

 Thompson, Mrs. Silvanus P., M.B.I, (the Author) — Silvanus Phillips Thomp- 

 son, D.Sc. LL.D. F.RS. His Life and Letters. 8vo. 1920. 

 Tohohu Imperial University, Sendai, Japan — Science Reports, 1st Series, 



Vol. VIII. No. 3. 4to. 1919. 

 United States, Bureau of Standards — Scientific Papers, Nos. 83, 351-355, 357, 



359-360, 362-363. 8vo. 1919. 

 Technologic Papers, Nos. 113-144. 8vo. 1920. 

 Circulars, Nos. 85-88. Svo. 1920. 

 United States Department of Agriculture — Journal of Agricultural Research, 



Vol. XVIII. Nos. 9-11. Svo. 1920. 

 Experiment Station Record, Vol. XLI. Nos. 8-9. Svo. 1920. 

 United States Geological Survey — Bulletin, Nos. 678, 710. 8vo. 1919. 

 Water Supply Papers, Nos. 429, 446, 457, 485. Svo. 1919. 

 Professional Papers, Nos. 113, 125. 4to. 1919. 

 United States, National Besearch Council — Reprint Series, No. 5. Problems 



of Sidereal Astronomy. Svo. 1919. 

 United States Patent Office— Official Gazette, Vol. CCLXXI. No. 3;— Vol. 



CCLXXII. No. 3. 8vo. 1920. 

 Vienna, Geological Institute — Verhandlungen, 1919. Svo. 

 Washingtoii, National Academy of Sciences — Proceedings, Vol. VI. No. 1. Svo. 



1920. 

 Zoological Society— Proceedings, 1919, Parts 3-4. Svo. 1920. 

 Zurich Naturforschenden Gesellschaft — Vierteljahrsschrift 1919, Heft 3-4. Svo. 



WEEKLY EVENING MEETING, 



Friday, April 16, 1920. 



Sir William Phipsox Beale, Bart., K.C. F.C.S. F.E.S., 

 Vice-President, in the Chair. 



H. Maxwell Lefroy, M.A. F.E.S. F.Z.S., Professor of Entomology, 

 Imperial College of Science, London. 



The Menace of Man's Dispersal of Insect Pests. 



[Abstract.] 



Ix the past destructive insects have been carried about the world on 

 plants and in merchandise : to England have come such pests as 

 codlin moth of apple, woolly aphis of apple, hessian fly of wheat, 



K 2 



