38 INTRODUCTION TO ZOOLOGY. 



means sheath Vings, aod it is so called from the 

 character of the fore wings. There are probably 

 25,000 species of beetles. All have biting mouth parts 

 and complete metamorphosis. 



Among the beetles are many injurious insects. 

 "We may mention the wire worms, which are larvae of 

 click beetles, and tlie curculios, the wood borer, the 

 carpet beetle, and the Dermestids, or fur beetles. 



Beetles are found almost everywhere. Some live 

 in the water, some in the ground, some in decayed 

 wood, and some on leaves. Some are predaceous and 

 prey upon other insects. 



THE GIAKT WATER BUG. 



1. Find the body divisions. 



2. Find the compound eyes. Are there ocelli? 



3. Find the antennae. Draw. 



4. Find the sucking tube. Is it segmented? How 

 many segments? To what is it homologous? 



5. In a groove on the upper side of the sucking 

 tube, find a hair-like organ. Of how many parts is it 

 composed? To what must these parts be homologous? 



6. Find a pointed flap lying on top of the groove 

 which conceals the hair-like organ, or punctorial 

 bristle. From its position, to what must it be homol- 

 ogous? 



7. Study the wings. What peculiarity has the 

 front pair? Draw. 



8. Notice how the wings lock together when folded 

 on the back. Find the little knob fitting into a groove 

 on the edge of the thorax, that holds the wings down 

 to the body. See how the fore and hind wings are 

 held together when the wings are spread. Draw. 



9. Identify the parts of the legs. How does the 

 hind leg differ from the fore leg? Is the femur of the 

 fore leg grooved or smooth? 



