552 Insects. 



THE CHEESE MITE. (Acarus siro.) 



THESE destructive little creatures differ from spiders in 

 having the thorax and abdomen united and covered with 

 the same skin, though it is contracted in one part. They 

 have also, when young, only six legs, though the two 

 others appear afterwards ; and their feet are armed with 

 strong hooks, which enable them to retain hold of the 

 cheese or other food, in which they take up their abode. 

 Their bodies are covered with hair, and their mouths 

 are furnished with strong mandibles, with which they 

 soon hew down huge rocks and mountains of cheese. 

 The eggs of these Mites are so small, that it has been 

 computed that a pigeon's egg would contain thirty mil- 

 lions of them. It must be observed that this Mite is 

 only found in dry cheese, in which it looks like reddish 

 dust. The cheese-hopper, found in moist rotten cheese, 

 is the maggot of a kind of fly. (Piophila Casei.) 



IV. Insects. 



INSECTS have all six legs and two antennae or feelers ; 

 and though the transformations they undergo differ 

 slightly in the different kinds, the following is the order 

 in which they occur : The perfect insect lays eggs, 

 which when hatched produce Iarva3 ; and which are called 

 grubs when they belong to beetles, maggots to flies, and 

 caterpillars to butterflies and moths. These larvae eat 

 voraciously ; and as they rapidly increase in size, they 

 generally moult, that is, change their skins, two or three 

 times. When the Iarva3 are full grown, they go into the 

 pupa state, in which they remain torpid and without 

 food for a considerable length of time, sometimes first 

 spinning a loose covering for the pupa called a cocoon. 

 The pupa is generally called a chrysalis ; but it is also 

 sometimes called a nymph, and sometimes an aurelia. 

 The last transformation is when the insect breaks from 

 its covering in a perfect form, when it is called the 



