290 NATURAL HISTORY OF AQUATIC INSECTS CH. 



Creator has provided them with hmbs suitable to their 

 work. The fore Hmbs are fitted for digging, as in 

 the Mole or Mole-cricket. Besides their feet, the 

 larvfE are also provided with jaws, each with two teeth, 

 like the pincers of Crabs, and these are well suited for 

 working in the mud. The larva; may be seen at work 

 if they are placed in water mixed with a little mud. 

 If the mud is not sufficient to cover the whole body, 

 they conceal first the head, then the body, and then 

 the tail, endeavouring all the time to complete their 

 dwelling. Anglers assure us that when the water of 

 the rivers sinks, the larvae work deeper and deeper 

 into the mud, rising again as the water rises. This, I 

 suppose, is indispensable for their breathing. They are 

 provided with many air-tubes for distributing the air 

 throughout the body. Access of air would be stopped 

 if they remained below after the water had risen. I 

 have often found that when taken out of their tubes and 

 placed on wet sand, they much prefer creeping out of 

 the water to burying themselves in the sand. The 

 reason of this may be that the warmth of the water is 

 injurious to them, as well as the want of mud. 



" As to the food of these larvae, it would be hard 

 to say what it was without the help of dissection, 

 but by this means I have discovered that they feed 

 upon mud only. Whenever the body is opened, mud 

 is found in the stomach and intestine. In the same 

 way certain caterpillars feed upon the same substance 

 of which they make their homes.^ 



^ Like Earthworms and many other burrowing animals, the 

 larva of Palingenia probably feeds not upon the mud itself, but 

 upon vegetable fragments scattered through it. The food of 



