80 



two, long, flattened processes, composed of several segments. 

 The basal segment, which is the largest and longest of the 

 segments, extends forward for about one-half the length of 

 the ligula, and is the palpifer ; the succeeding three seg- 

 ments compose the labial palpus. 



The proximal one of these segments is the largest and ap- 

 pears to be a direct continuation of the palpifer, separated 

 only by a narrow straight suture ; the reniaining two seg- 

 ments are very small. 



Make a drawing of the cephalic aspect of the head show- 

 ing the fixed and movable parts. 



PIERCING AND SUCKING MOUTH-PARTS. 



Among the insects whose mouth-parts are fitted exclu- 

 sively for piercing and sucking (or sucking alone) the man- 

 dibles, if present, are modified to form slender elongate sty- 

 lets or blades. 



This is the condition presented by the Hemiptera, and 

 some of the Diptera ; with most of the Diptera and all of the 

 Lepidoptera (excepting Eriocephala) the mandibles are com- 

 pletely lost, or are so atrophied as to be functionless. As 

 examples of insects with strictly sucking mouth-parts the 

 student may examine a Cicada (Hemiptera), a horse-fly and 

 a house-fly (Diptera, one with and the other without mandi- 

 bles) and a butterfly (Lepidoptera). 



MOUTH-PARTS OF A CICADA. 



{Cicada sp.; order Hemiptera.) 



The sucking beak, tapering from base to tip, will be 

 found, in dried specimens, usually appressed to the ventral 

 surface of the body of the Cicada. 



Remove the head with the beak from the dried specimen, 



