SPECIAL PROBLEMS OF INSECT CONTROL 151 



Water will not do this, because the openings are protected 

 against its entrance by oily secretions. Compare the effect 

 of dipping an insect into water and into kerosene. 



Next, beginning at the head, study all organs and mov- 

 able parts (appendages) : the eyes, feelers (antennge, replacing 



Head, Prothorax Mesothorax Metathorax Abdomen 

 Compound Eye \ / j 



Simple Eye/ \ ^ ^ / / R .^ mng / 



iK^' Ear 



Ante/nn&\ 

 Latirum \ 



Spiracles 

 "-Trochanter 



Mandible 

 Maxilla 



Femur 



Tibia 



Tarsus 



Labium 



Mouth-Paris 



FIG. 77. External anatomy of the grasshopper 



ears and nose as sense organs, at least partly), mouth parts 

 (very complicated, consisting typically of an upper and lower- 

 lip (labrum and labium) and two pairs of jaws (mandibles 

 and maxillae), which move sidewise instead of up and down). 

 Watch a caterpillar or grasshopper eat a leaf and see if you 

 can discover why the jaws move sidewise. A study of mouth 

 parts is again important with reference to methods of destroy- 

 ing insects. Those that bite and chew can be killed by spraying 



