228 



SUBKIKGDOM ARTICULATA. 



residence. This is closed with a water-tight trap-door, 

 having an elastic hinge, the outside 

 mimicking the soil around, and held 

 down with the whole force of the 

 spider's claws fastened on the side 

 of the door opposite the hinge. 



ORDER PEDIPALPI. 



General Characteristics. The 

 Pedipalpi (foot-feelers) have large 

 maxillary palpi and the jointed ab- 

 domen prolonged sometimes into a 

 tail.* 



Scorpionidae. Tne Scorpion has a powerful poison-sting 

 i the end of its tail-like abdomen, which wounds by curving 



Fig. 390. 



Nest of MygcUe. 



Buthus carolini&nm, Scorpion. \. 



over the back, while the victim is held between the forceps- 

 like feelers. Its wounds are rarely fatal, the antidote being 

 hartshorn. 



ORDER ACARINA. 



General Characteristics. The Acarina have the 

 mouth adapted either for sucking or biting. They are of 

 small size, and generally parasitic. 



Acaridae. The ItcJi-mite, burrowing in the flesh, multi- 



* The Phalangidse include the Harvest-man or " Daddy-long-legs " (not the crane- 

 fly), which is carnivorous, feeding especially upon the Aphidse, and is hence very 

 beneficial. 



