RELATION TO THE HOUSEHOLD 221 



shirt front. They are rarely abundant enough to be a 

 real nuisance, and wherever it is necessary to deal with 

 them they yield readily enough to pyrethrum or gaso- 

 line whichever may be indicated; naphthaline serves 

 very nicely as a repellent wherever one is necessary. 

 Ordinarily, killing the specimens as they come under 

 observation answers every purpose. 



A little higher in the scale of development come the 

 "book lice" belonging to the family Psocidce, allies of 

 and somewhat resembling the 

 biting lice that have been al- 

 ready dealt with in their rela- 

 tions to other animals. Indeed, 

 as a rule housekeepers when 

 they notice these little insects 

 among their stores of linen or 

 in dusty corners of drawers, 

 suspect them of being really 

 parasites or true lice. But all 

 lice, whether of the biting or 

 sucking variety, are awkward, FIG. 104. A book louse, 

 slow-moving creatures on a 



level surface, while these little Psocids are active and 

 agile, running backward or forward with equal readi- 

 ness, and so spry as to be not easily captured. When 

 captured, instead of being tough and leathery in texture, 

 requiring an effort to crush, they are soft and go to 

 pieces at a touch. They are never found on animals of 

 any kind, and what they are after is the little organic 

 particles that they get from any sort of dry animal or 

 vegetable matter. A dead fly will be reduced to a fine 

 powder by them in a few days when they are abundant, 

 and in collections they are occasionally something of a 

 nuisance; but almost any pungent odor drives them 

 away, and besides we have always the resource of not 



