64 THE INSECT WORLD. 
may be seen an elevation, a sort of tumour, termed a bot—a bump, 
as Réaumur 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 Réaumur’s memoirs, represents 
the bots of which we speak. 
The country people are well aware of the nature and cause of 
these bots. They know that each one contains a worm, that 

Fig. 46.—Bumps produced on Cattle by the larve of the Bot-fly. 
this worm comes from a fly, and that later it will be transformed 
into a fly itself. Hach of these bots has in its interior a cavity, 
occupied by a larva, which, as well as the bot, 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. Hach tumour is provided with 
a small opening by which the larva breathes. 
