THE INSECT WORLD. 



69 



sites by their very rapid motions and their long antennae or 

 feelers. Their food is starch, where they can get it, or dry ani- 

 mal or vegetable matters, and they can be driven out by a free 

 use of naphthaline crystals. Their injury in libraries is done by 

 eating the starched surface of bindings, plates, and pages, and 

 so disfiguring them. 



The forms just described are all wingless throughout their en- 

 tire life, Atropos {Clothilla) divinatoria and A. pulsatoria being 

 common species. In some mysterious way the term "death- 

 watch" has been applied to these creatures, and they have been 

 credited with making the ticking sound often heard at night in 

 old houses, and which is supposed to give warning of a death to 

 come. 



But there are some winged forms, and these somewhat resem- 



FiG. 37. 



Psocus lineatus, much enlarged. 



ble overgrown plant lice, differing, of course, by the mandibulate 

 mouth. These winged Psocids sometimes occur in great num- 

 bers on the bark of trees, in my experience most often on cherry 

 and orange, where they feed upon lichens and other dry vege- 

 table matter. They sometimes create alarm when great numbers 

 are noticed by the farmer ; but none of them are in the least in- 

 jurious. They are more cylindrical in appearance than the wing- 

 less forms, and the thoracic parts are better developed and larger 

 than the head, which bears the same coarsely granulated eyes 

 and long antennae. When a group of specimens is disturbed 

 they run in every direction, and often drop to the ground 

 rather than use their wings in flight. Altogether, this family 



