THYSANURA. 
85 
water appear to be covered by a moving mass of minute 
grains which become more active when disturbed. These 
masses as well as the dark specks on snow consist of thou¬ 
sands of little creatures that are provided with a wonderful 
means of jumping. There is on the end of the body a tail-like 
organ that is bent under when the insect is at rest, and that 
reaches almost to the head ; this when suddenly straightened 
throws the insect high in the air and several feet away. This 
action is like a spring-board jump, only these little fellows 
always carry their spring-boards with them, and have thus 
won the name of Spring-tails. The species upon snow, called 
the Snow-flea, Achorutes nivicola (Ach-o-ru'tes ni-vic'o-la), 
sometimes proves a nuisance in maple sugar-bushes by get¬ 
ting into the sap. Through a micro¬ 
scope a Spring-tail appears very ab¬ 
surd, it has long antennae and large, 
dark eye-spots on the face, which, to¬ 
gether with the long hair that sticks 
forward on the head and thorax, 
give the creature a look of solemn 
n rv • rr • Fig. 93 .—Papirtus fuscus. (After 
fierceness. Different species may Lubbock.) 
be found at almost any time of the year in damp places. 
Figure 93 represents one of these. In many forms the 
body is much more slender than in that figured. 
