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now so used to, and skillful in the matter as to be able to 

 see, and show them, beating almost when I please, by 

 having a paper with some of them in it conveniently 

 placed, and imitating their pulsation, which they would 

 readily answer." He found that they would tick con- 

 tinuously for hours with regular intervals between each 

 beat, thus greatly resembling the ticking of a watch. 

 The author is not aware that any careful observations 

 on the ticking habits of psocids have been made by recent 

 observers and the question still awaits a thorough in- 

 vestigation. The true death-watch psocid is said to be 

 Clothilla pulsatoria, although some confusion regarding 

 the species seems to exist. 



There are other species of the Psocidse, larger and with 

 wings, that resemble plant lice and live out-of-doors on 

 the trunks of trees, old walls, and stones covered with 

 lichens and moss. These never become troublesome in 

 dwelling-houses. 



Food and habits of the psocids. — The book-lice have 

 biting mouth parts and live upon the paste of book bind- 

 ings and paper and upon animal or decaying vegetable 

 matter. They also feed on flour, meal, and other cereals, 

 and are quite destructive to specimens in natural history 

 collections, especially to insect collections. The author 

 has noticed this particularly in the South, where the bodies 

 of small insects, like mosquitoes, have been badly eaten 

 and the specimens practically ruined in a very short time. 



These insects are also known to abound in barns among 

 straw. Hagen says that he had "on one occasion found 

 more than half of the refuse material left in a barn after 

 threshing the grain to consist of a small species of psocus." 

 Lintner tells us that McLachlan of London, England, has 



