186 



NATURAL HISTORY 



place the dragon-flies at the base of the insect series ; but they certainly 

 are entitled to a higher rank than the cockroaches and the locusts. In 

 European works they are always assigned their proper position. 



Passing by some of the less interesting forms, the first we have to 

 notice is the familiar little book-louse, so frequently seen running over 

 the pages of books, especially those left in dusty places. These they 

 sometimes damage considerably by gnawing the paper. In this form 

 the wings are extremely rudimentary, — may almost be said to be absent, 



as they form but little scales or patches of no functional importance. 



In England this species shares with one of the beetles the common name 

 'death-watch,' and is said to make a ticking sort of a noise, which when 



heard is believed to indicate that one of the 

 family is soon to die. Allied forms larger in 

 size and darker in color abound on fences and 

 trees ; and these eventually have wings, and 

 then look much like the winged plant-lice, of 

 which we shall have more to say farther on. 

 Our figure represents one of these winged forms, 

 natural size, and another with its wings spread, 

 enlarged. In the spring and early summer the 

 unfledged larvae abound ; but later in the year, 

 the perfect forms appear. What they feed upon is as yet unsettled. 



Closely allied to these minute forms in structure are the celebrated 

 white ants, of which pages might be written. In their general appearance, 

 as well as in their habits, they present a close similarity to the true ants, 

 and to this fact they owe their common name. Their scientific name is 

 Termes, and they frequently figure in books as termites, the plural form of 



Fig. 170. — Psocus. 



Fig. 171. — Male of the white ants (Termes). 



the generic name. In reality they are not ants at all, but belong to nearly 

 the opposite extreme of the insect series. 



In these forms we find four different kinds of individuals. First come 

 the males, which are provided with wings ; and then the females, which at 

 first resemble the males, but which later change in a remarkable way, as 

 will be described farther on. The third are smaller individuals, with small 

 luads and jaws, and without wings. In them the sexual organs are not 



