BRISTLETAILS AND SPRINGTAILS 



75 



the surface of stagnant pools, in manure piles, in the decaying 

 hollows of trees, in gardens, hotbeds, window boxes, and, in general, 

 in moist places where decaying vegetation 

 is found. They are usually microscopic in 

 size, from one tenth to one twentieth of an 

 inch long, but have an exceedingly inter- 

 esting structure. Projecting forward from 

 the underside of the next to the last ab- 

 dominal segment is a long abdominal ap- 

 pendage, or spring, by the extension of 

 which the insect is enabled to shoot for- 

 ward as if shot from a catapult, jumping a 

 considerable distance. As the springtails 

 feed only on decaying vegetation, they are 

 never injurious, unless exceptional num- 



FIG. 90. Underside of the 

 American springtail (Lepido- 

 cyrtus americanus] with the 



bers render them a nuisance. Occasionally s P rin s f olded underneath the 



. body. (Much enlarged) 



such immense numbers of small spnng- 



(After Howard and Marlatt) 



tails are found in manure heaps or on the 



surface of stagnant pools or ponds as to attract attention to them. 

 Many of these little springtails are prettily colored with patterns 

 composed of very minute scales. For this reason they are often 

 used as test objects for microscopes, the quality of the lens being 

 determined by its efficiency in revealing the very fine markings on 

 these tiny scales. 



