i 4 4 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



very effective. For with each bite of leaf the insect will 

 get a little dose of poison, and a few such doses will kill it. 

 Students of economic entomology should therefore pay special 

 attention to insect mouth-parts. The following brief descrip- 

 tion of several different types of mouth parts may serve as an 

 introduction to this study. 



Mouth -parts of Grasshoppers. A familiar type of the biting 

 insect mouth is that of the grasshopper. Here the 



FIG. 60. Mouth-parts of grasshopper, a, Labrum; b, tongue; c, 

 mandibles; d, maxillas; e, labium; m.x p., maxillary palpi; I. p., labial 

 palpus. (Greatly magnified.) 



upper lip or labrum, inclosing the mouth above is broad and 

 flap-like, and the jaws, or mandibles, which like the honey- 

 bee's, open and shut laterally, are large, strong, heavily 

 chitinized and have their biting edges furnished with small 

 tooth-like projections. The maxilla, sometimes called second 

 pair of jaws, which, with the mandibles, close the mouth at 

 the sides, are each composed of several parts, movable on 

 each other, of which one is a small feeler, or maxillary palpus, 

 bearing at its tip many taste buds. The under lip, or labium, 

 is a broad flap-like piece also made up of several articulating 



