CHAPTER XIV 



SOME TROUBLESOME INVADERS OF THE 

 HOUSEHOLD 



There are a few insects and related animals that nor- 

 mally live out-of-doors but at times invade the house 

 and cause annoyance and injury. Two of the mites, 

 certain scorpions, and the house centipede are among 

 such offenders. White ants invade the house and 

 undermine the framework of buildings, while book-lice 

 often increase in enormous numbers and the spring-tails 

 appear in unexpected places. 



A PREDACEOUS MITE 



Pediculoides ventricosus 



Webster has given a most interesting account of a mite 

 (P. ventricosus) that has proven noxious to man. Un- 

 doubtedly, the attacks of this mite have been diagnosed 

 as those of chiggers. In 1908 and 1909, threshermen, 

 harvest hands, workers in potteries, and other laborers 

 who handled straw in Ohio suffered greatly from what 

 was supposed to be chiggers. In the light of present 

 knowledge it is probably safe to say that most of these 

 attacks were by the predaceous mite named above, and 

 not by chiggers. Webster's researches have shown that 

 this mite is parasitic upon the wheat joint worm and upon 



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