54 LOWER PTERYCOTA 



caught with difficulty. If caught tlie scaly covering brushes 

 oft' readily as a fine, whitish dust. 



A related species, Lepisma saccharina, is found, especially 

 in pantries, bakeries, or in places wdiere they can secure 

 starchy materials for food. In some cases they attack the 

 bindings of books or the starchy covering of la})els, and may 

 cause a good deal of annoyance and injury- in libraries. 



Order COLLEMBOLA. 



This order, including the spring tails, is characterized 

 at once by the strong spring which is folded under the 

 abdomen and which catches into a loop on the thorax. The 

 release of the spring from this throws the insect into the 

 air with a sudden spring, which doubtless serves it as a 

 protection against certain kinds of enemies. The species 

 are generally found in moist places in cellars, under loose 

 boards, chii)s, or stones, and some of them are found ftoating 

 on the surface of water in quiet pools or along the margins 

 of streams or ponds. They feed mainly on decaying organic 

 matter and are of little economic concern, but a few species 

 are credited with feeding on vegetation, especially in green- 

 houses. 



THE LOWER WINGED INSECTS (PTERYGOTA). 



The remaining groups are primarily winged, and a numl)er 

 of the lower orders may be grouped together in this chapter. 



Order ORTHOPTERA. 



This order, including cockroaches, crickets, grasshoppers, 

 etc., is distinguished by the biting mouth parts being rather 

 simple and ])rimiti\e in structure, the wings of rather simple 

 pattern, the front wings narrow and the hind wings broad 

 and folded in a fan-like manner, so as to be coverefl by the 

 fore wings when at rest. 



They differ in their mode of locomotion, some having 

 rapid running movement, using all of the legs equally well, 

 others walking slowly, and others, more specialized, having 



