Packard.] ESTSECTS OP THE POND AND STREAM. 133 



on the struggling worm, which is nailed to the leg by a spine 

 opposite the end of the claw. Why its bod}' is so long and 

 linear in shape, we cannot imagine, unless for the purpose 

 of concealment and protection, as its movements are labored 

 and slow, as are those of Belostoma, its near ally, which, as 



Fig. 93. 



Ilanatra. 



has been remarked by others, closely resembles a dead loaf, 

 as it lies at the bottom of the pond in wait for its prey. 

 So small a proportion of insects arc aquatic that the 

 question arises whether those that do live in our ponds and 

 streams may not be the descendants of terrestrial forms. 

 The ocean is the parent of all life ultimately, but only a 



5 



