Book-Lice or Psocids. 3 
merely because they are often seen on books, and because they have 
‘some resemblance to chicken lice. Usually they attract attention 
more because of their annoying presence than on account of the 
actual damage they do. Ordinarily they are not regarded as in- 
jurious pests, yet they have jaws with which, in spite of their deli- 
eate structure, they can gnaw. They feed upon decaying timbers, 
feathers, straw, and hair, and upon flour, meal, and other farinaceous 
substances, and even dust. They eat the starchy paste in book bind- 
ings, wall paper, and photographs. Indeed, they are general feeders 
upon dead and decaying animal and vegetable matter. 
Book-lice thrive best in closed rooms that are warm and damp. 
Seldom are they noticed in light, airy rooms in constant use, but 
more often are found in numbers in darkened, damp parlors kept 
closed except on special occasions, and in houses that have been 
closed all summer. They die off during cold weather, but may 
leave behind them eggs which hatch the following spring to furnish 
the infestation for the succeeding year. Ordinarily they do not 
become abundant enough to attract attention until late summer or 
early fall. 
CONDITIONS FAVORABLE TO THEIR INCREASE. 
As stated, book-lice are not especially injurious in dwelling houses, 
barracks, or factories. It is only when materials which they are 
capable of injuring, or in which they can breed, are left undisturbed 
for long periods that they are likely to increase to such an extent 
as to cause serious damage or annoyance. Occasionally they multi- 
ply excessively in some available food supply, and swarm over a 
house to the consternation of the housekeeper, but fortunately such 
instances are rare. Upholstered furniture and mattresses stuffed 
with straw, husks, hair, feathers, or moss are specially favorable 
places for their multiplication, and in the worst cases of infestation 
on record, the psocids have come from such sources. They have been 
found in myriads in straw in barns and stables, in the straw cover- 
ings of wine bottles in cellars, and in rooms in which tow used in 
the manufacture of upholstered furniture is kept. 
One record on file indicates the usual history of infestation. Ina 
new house kept by very neat occupants, a mattress of hair and corn 
husks which had been purchased not more than six months before 
was found in a badly infested condition after the house had been . 
closed about six weeks. 
It was so covered with psocids that a pin could not be stuck into the mattress 
without piercing an insect. The side of the sheet next to the mattress was 
likewise covered, and a further search showed the walls and the entire house 
to be swarming with the tiny pests. A sweep of the hand over the walls 
would gather them by the thousands. Bureau drawers were swarming with 
