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^inicellular organisms, Protozoa and Bacteria, the valuable con- 

 tributions made by the President of this Club are too universally- 

 known to require more than mention on this occasion. Before 

 proceeding further, the lecturer said be would like to pay a 

 tribute to a late member of the Club, Mr. W. Wesche, whose 

 pioneer work on mosquito larvae the last work he was permitted 

 to do carried out under great difficulties, will ever stand out in 

 the history of economic entomology. It is almost unnecessary to 

 point out that in the animal kingdom no group is more intimately 

 connected with the bionomics of the world at large than that 

 designated by the general name " insects," and at the same 

 time no group is so prolific in its effects both for good and evil. 

 We can never forget the jjart played by insects in fertilisation, 

 their utility as scavengers, their natural products (such as honey, 

 wax, silk and colouring matters), and the effect of the gorgeous- 

 ness of their subtle colouring on the aesthetic sense of man. 

 Neither can w^e forget, for example, the destruction of crops by 

 locusts, the effect of weevils on cotton and grain, the blight 

 -of vines by Phylloxera, and the injury wrought by ants and 

 termites ; but the dark side of the picture does not even end here. 

 Who can forget the enormous annual loss of life and the infinite 

 suffering to man and beast caused by insects, both directly and 

 indirectly ? directly by themselves being the actual cause of the 

 disease, indirectly by their mechanical dissemination of patho- 

 genic bacilli, or by acting as intermediate hosts for other patho- 

 genic organisms ? The role played by insects in connection with 

 disease is consequently threefold: (1) As actual parasites, (2) as 

 mechanical transmitters, (3) as intermediate hosts of pathogenic 

 organisms. In the first case actual parasites certain insects 

 are themselves the immediate cause of disease, inasmuch as they 

 pass part of their existence in the bodies of men and animals, 

 usually beneath the skin, but occasionally in deeper tissues. This 

 phenomenon is known as myiasis, and already over twenty species 

 of diptera are known whose larvae have been found in, or 

 expelled from, the human intestine. In such cases the ov^a of 

 the insect have been swallowed with food on which they were 

 deposited, and have continued their development in the alimentary 

 canal, where they often give rise to strong inflammatory com- 

 plications. Then we have the case of the screw-worm, the adult 

 of which lays a mass of 300 or 400 eggs on the surface of wounds, 



