04 



THE INSECT WOELD. 



may be seen an elevation, a sort of tumour, a bump, as Keaumur 

 calls it, comparing it more or less justly to the bump caused 

 on a man's head by a severe blow. 



Fig. 46, taken from a drawing in Reaumur's memoirs, represents 

 the bumps of which we speak. 



The country people are well aware of the nature and cause of 

 these bumps. They know that each one contains a worm, that 



Fig. 46. Bumps produced on cattle by the larvae of the Bot-rty. 



this worm comes from a fly, and that later it will be transformed 

 into a fly itself. Each of these bumps has in its interior a cavity, 

 occupied by the larva, which, as well as the bump, increases in 

 size as the larva becomes developed. 



It is generally on young cows or young bullocks in fact, on 

 cattle of from two to three years of age that these tumours exist, 

 and they are rarely to be seen on old animals. The fly, which by 

 piercing the skin occasions these tumours, always chooses those 

 whose skin offers little resistance. Each tumour is provided with 

 a small opening by which the larva breathes. 



