332 



THE MICROSCOPE, 



and observe, in the first place, that the whole of its development may 

 be clearly traced out in almost every sample of brown sugar. The 



Acarus sacchari is first visible as a 

 rounded body, or egg ; this gradu- 

 ally enlarges, and becomes elon- 

 gated and cylindrical, until it is 

 about twice as long as broad ; after 

 a time, from the sides and one ex- 

 tremity of this ovum the legs and 

 proboscis begin to protrude. These 

 stages of the development of the 

 acarus are exhibited in fig. 158. 



The Acarus farince, or Flour- 

 mite. This is of occasional occur- 

 rence in flour, but is never present 

 unless it has become damaged. 

 Any flour, therefore, containing 

 the insect in question is in a state 

 unfit for consumption. We believe 

 that it is found more frequently in 

 the flour of the Leguminosce than 

 that of the Graminece. 



This acarus differs considerably 

 in structure from the sugar-mite, 

 and particularly in its pennate setee. 

 fig. 159. Acarus farince, or Meal-mite, D r . Burnett established to his 



magnified 250 diameters. sat i s f act ion the following facts : 1 . 



That although there are single species of parasites peculiar to particular 



fig. 160. 

 Larva of Parasite of Hornlill. 



fig. 161. 



1. Hippolosca Hirundinis. 



2. Nirmi, parasites infesting the Swallow. 



