INSECTS ARACHNIDA DIAGRAM 6. 149 



throws the corpse away, or sometimes surrounds it with silken 

 threads and leaves it where it K It repairs the meshes which 

 have been broken, and returns to wait for another victim. All 

 spiders do not lead this sedentary existence ; some species do 

 not make a web, and simply stretch threads here and there. 

 They are found running in the fields, and some of them leap 

 with great agility. They are called running and hunting 

 spiders. 



Spiders are sometimes found which carry a large silken ball 

 attached to their abdomen which they never abandon. This 

 ball is filled with eggs which the female carries everywhere with 

 her. Other species also put their eggs into a silken bag, but 

 they hang it in some part of their web where it will be secure. 



It was formerly pretended that there was a spider in Italy 

 called tarantula, the bite of which causes a desire to dance ; 

 but this is a fable, like so many other tales which are told of 

 animals. 



Mites and the ItcJi-insect. The mites which live in cheese 

 have also eight legs, and consequently be- 

 long to the class Arachnida. Their history 

 would not be very interesting if their form 

 did not resemble that of another animal 

 which is a parasite on man, and which 

 produces the disease called the itch. It 

 is still smaller than the cheese-mite, and 

 makes galleries of about a quarter of an inch / , 

 in length under the epidermis. As it works 

 chiefly at night, it is then that it causes the Itch-mite 



most violent itching. The itch is caught by highly magnified, 

 contact with an infected person, when the itch-mite passes 

 from one person to another. It is always desirable to get 

 rid of these parasites as soon as possible ; but as they are 

 very small and hidden under the skin, medical assistance is 

 necessary. The dog, cat, horse, and dromedary have para- 

 sites which cause itch in them also. These are not the 



