2 4 o MINUTE MARVELS OF NATURE 



tubes converging to the two larger ones, each tube 

 kept open by numerous horny half-rings, scarcely 

 visible on the photograph, constitute together 



Proboscis of a hover-fly 



with other internal parts a marvellous mechanism 

 for facilitating the flow of fluid substances by 

 capillary attraction towards the mouth. During 

 the process, saliva is first secreted by the salivary 

 ducts and rubbed about until some of the food- 

 stuff is dissolved, after which it is sucked up again. 

 The two bristly club-shaped organs on each vS.i 



