62 ROMANCE OF THE INSECT WORLD CHAP. 



ception, Lepidoptera hold the highest rank as 

 regards special adaptation to flowers. They 

 take little thought for their young, and the mouth 

 has been free to adapt itself to the easiest possible 

 winning of a floral liquid diet. Many perfect 

 insects have similar tendencies as to food, but have 

 been hampered with additional desires. The adapta- 

 tion is attained by the astonishing development of 

 the maxillae, to the almost total abortion* or suppres- 

 sion of the rest of the mouth-parts. The atrophied 

 condition of the now useless organs affords a beautiful 

 illustration of the law that in proportion as the func- 

 tions of an organ become suspended, or are not 

 required, by the employment of other parts, the organ 

 itself deteriorates and becomes useless, and perhaps 

 entirely disappears. 



The maxillae are modified to take food in a liquid 

 state, and still further the food is produced in ex- 

 tremely inaccessible situations in the deep hidden 

 chalices or nectaries of flowers. Thus they assume 

 the shape of an elongated, slender, and flexible 

 sucking-tube. Each maxilla is transformed into an 

 immensely long rounded filament,* convex on the 

 outer surface, concave on the inner side, and the tube 

 is formed by the close approximation of the two 

 organs. Throughout almost the entire length of both 

 filaments one or more large tracheal vessels run, which 

 are connected with the tracheae of the head. They 

 divide into a number of minute ramifications as they 

 approach the extremity of the organ, but have 

 no communication with the external surface. The 

 presence of these vessels has given rise to the idea 



