280 ELEMENTARY STUDIES IN INSECT LIFE 



examples of the mandibulate type. The mouth-parts of 

 the cicada, sometimes called harvest-fly or locust, illus- 

 trate the structure of the haustellate mouth. Specimens 

 just from the cyanide bottle or preserving-fluid can 

 be studied without further preparation. Dried speci- 

 mens will require boiling in water until soft and plia- 

 ble. Remove the head with the beak from the body 

 of the specimen ; examine the beak before dissecting. 



The primitive or earlier insects had biting mouth- 

 parts ; the haustellate or sucking mouth is a later de- 

 velopment. This mouth structure is therefore a special- 

 ized form. That is, it has been peculiarly developed 

 for a certain purpose, from, we are led to believe, the 

 primitive mandibulate mouth. So, in discussing these 

 sucking mouth-parts, it is the endeavor to trace each 

 back to its primitive organ. The terms used, then, 

 in naming the organs of the sucking mouth, are as far 

 as possible the same as those used in naming the parts 

 of the biting mouth. These terms, such as mandible 

 and maxilla, are not used to name the parts of the 

 sucking mouth to signify that they are used for chew- 

 ing. The parts are so designated because it is gen- 

 erally believed that the parts so named were once a 

 true mandible or a true maxilla. But certain condi- 

 tions arose which made it necessary for these insects to 

 secure their nourishment from the juices under the 

 bark of trees, instead of chewing the foliage. These 

 biting mouth-parts gradually developed by long use into 

 tube-like structures adapted to the required work. 



The names given these are given, therefore, because 

 it is generally believed that the sucking mouth-parts, so 

 named, represent the present development or condition 



