ORDER HEMIPTERA. 



77 



morphosis. Fig. 63 represents the transformations of the 

 chinch-bug, the young having no wings. After reaching 



FIG 62 Longitudinal section of bug's head. Ibr, labrum; Ib, labium; md, 

 mandible; mx, maxilla; sg, salivary gland (the arrows pointing outward 

 show the course of the salivary duct into the mouth; the inward-pointing 

 arrows indicate the throat and the direction taken by the food in passing to 

 the stomach); I, t, x, muscles which elevate the roof of the mouth. After 

 Graber. 



the stage e, the wings appear as in the stages/ and g. This 

 bug does immense harm to farmers by sucking the sap of 

 wheat and corn. 



Certain species of Hemiptera are apterous; the sexes 



FIG. 63. The Chinch-bug and its early stages, a, b, eggs; c, e, larval stages; /, g, 

 pupae; ;', beak; d, tarsus of larva; j, tarsus of perfect bug; h, leg of ditto. 



differ in the form of the body and fore wings, in the second 

 joints of their antennae, and in their tarsi ; while the females 

 are generally larger and more robust than the males, but 

 they do not commonly differ much in color. (Darwin's 

 Descent of Man, i. 339.) 



