BOOK-LOUSE AND SILVER-FISH INSECT 309 



Neuroptera, i.e., false Neuroptera. If Atropos were ever 

 found with wings, they would no doubt be of the nature 

 of the second figure rather than of the first ; but no such 

 occurrence is known ; if, on the other hand, the winged 

 Psocidce were deprived of wings, they would somewhat 

 resemble Atropos, and in their earlier stages, when 

 they are wingless, they do actually exhibit a tolerably 

 close approximation to it. These facts are a sufficient 

 justification for including it in the same family. 



The book-louse is most abundant in summer time, 

 when it may be found, not only in neglected collections 

 of animals or plants, but in cupboards, on window 

 ledges and library shelves, and generally amongst old 

 books (whence its popular name) or stores of any kind, 

 and-the more undisturbed the stores the more the insects 

 will flourish. With their stout little jaws they some- 

 times do considerable damage to books, dried plants, 

 insects, &c., nibbling away at the leaves and covers of 

 the former, and destroying all the smaller and more 

 easily accessible portions of the latter. Farinaceous sub- 

 stances seem to be peculiarly acceptable to them, and 

 one of the most flourishing colonies that have come 

 under my notice was in a small quantity of "oat flour," 

 which had been left for some years in a tin canister. 

 The little creatures had the store all to themselves, and 

 were perfectly revelling in it. 



They are very interesting little things to watch the 

 movements of, and this is easily done by enclosing them 

 in a glass- topped box, and examining them under a low 

 power, say a two-inch objective, of the compound micro- 

 scope. There is a sprightliness and apparent intelligence 

 about their actions which is quite surprising in creatures 

 of such very minute size; and as one gazes at them 

 down the tubes of the instrument, one cannot help 



