CHAPTER VI. 



SPECIALIZED MOUTH-PARTS OF INSECTS. 



The mouth-parts of the locust and beetle have already 

 been studied ; they represent, as a type, the generalized bit- 

 ing mouth-parts of insects ; (biting mouth-parts of general 

 identity with this type are found in the Neuroptera and in 

 the pseudo-neuropterous groups (the bird-lice, white-ants, 

 dragon flies, stone flies and others). The student has al- 

 ready become acquainted with the specialized, sucking 

 mouth-parts of the butterfly. Another type of sucking 

 mouth-parts, one in which all the parts of the mouth are 

 represented, is presented by the Hemiptera, for an easily ob- 

 tained and easily studied example of which we have chosen 

 the Dog-day Cicada, Cicada dorsata. As typical of the 

 piercing and sucking (or lapping) mouth-parts of the Dip- 

 tera we have described the mouth-parts of the horse-fly, 

 Tabanus sp., and of a house-fly, Musca domestica, speci- 

 mens of which are easily obtainable. Finally for that inter- 

 esting type of combined biting and sucking (or lapping) 

 mouth-parts presented by the Hymenoptera, we have se- 

 lected, as example, the common honey-bee, Apis mellifica. 

 The homologies of the variously appearing parts constitut- 

 ing these different types should be always held in mind. 



THE MOUTH PARTS OP THE DOG-DAY CICADA. 



( Cicada dorsata. ) 



The sucking beak, tapering from base to tip, arising from 

 the caudo- ventral part of the head, will be found in dried 

 specimens usually appressed to the ventral surface of the 

 body of the Cicada. The mouth-parts may be examined 



