100 FIELD ZOOLOGY. 



legs. If you find the beak, turn the insect over on its 

 face to discover whether the wings have an opaque and 

 a transparent portion. If both facts are true, you may be 

 sure that you have another bug; and this sort is what is 

 called the giant water bug. Having captured and studied 

 these bugs, empty your pail back into the pond ; you have 

 all the requisite knowledge of them, and they are useful 

 and must be left to do their life work by living out their 



FIG. 44. Giant water bug. Benacus griseus. Slightly reduced. (Folsom.} 



alloted days, and thus fulfilling their mission. You have 

 the really valuable knowledge when you have found that 

 they are valuable by discovering what they are eating; 

 if you want to know their real names, they can be brought 

 home in the pail and kept in water renewed at least every 

 day, with flies occasionally fed to them, while you are 

 studying their structure and make-up carefully enough to 

 recognize their accurate description in some one of the 

 insect manuals. All three of these insects have good' 



