THE INSECT WORLD. 



57 



ered nearly half an inch in depth by a solid mass of these little 

 creatures not one-sixteenth of an inch in length. Frequently a 



Fig. 29. 



Papyrus species : showing spring curved under the body. 



Fig. 30. 



sudden rise of water on meadow or bog land drives them out of 

 their hiding-places, and they leap about on its surface for a time 

 as readily as they do on land. I have seen, on cranberry bogs 

 reflowed late in May, square rods of the surface so densely cov- 

 ered that nothing of the water was visible. 



They are often found in damp cellars, on any vegetable matter 

 stored there, and are sometimes ac- 

 cused of promoting decay. In the 

 fields a cut potato placed underground 

 may attract dozens of specimens that 

 feed upon the juices of the raw sur- 

 face, and they have been therefore ac- 

 cused of producing scabby potatoes. 

 They are of all colors, but usually 

 slate-gray or yellowish, the markings 

 sometimes quite pretty and distinct. 



As a matter of fact, these insects 

 are never injurious. Healthy vege- 

 table tissue is not attacked by them, 

 and their mouth parts are adapted for 

 feeding on soft or moist tissues only : 

 hence a decayed or bleeding spot at- 

 tracts them. They are sure to occur in manure and on manured 

 land, and can be kept out to a large extent by using only mineral 



A Podurid, or spring-tail, found on 

 manure beds. 



