HEMIPTERA 



141 



of plants. The sucking beak consists of the labium, which, to- 

 gether with the labial palpi, is modified into a jointed sheath. 

 This incloses the mandibles and maxillae, which are changed 

 into long, piercing stylets. 1 The labrum or upper lip is small or 

 rudimentary. There are usually four wings. In the typical 

 Hemiptera, as exemplified in the sub-order Heterop'tera, the 

 character of the anterior wings is a distinguishing feature. 

 The basal portions of these wings are thickened and parch- 

 ment-like, while the terminal portions are membranous and 

 overlap when the wings are folded over the back. From the 

 character of these wings the order gets its name hemi, half, 



FFig. 111. Bed-bug (Ci'mexlectular'ius): a, Adult female gorged with 

 blood; b, same from below; c, rudimentary wing-pad; d, mouth parts. 

 All enlarged. (Marlatt, Bull. U. S. Dept. of Agriculture, 1896.) 



and pteron, a wing, i. e., the Hemip'tera or " half-winged " 

 insect. The second pair of wings are membranous and fold un- 

 der the fore wings when not in use. The electric-light bugs, 

 bed-bugs, water-bugs, and squash-bugs are familiar examples. 

 In the sub-order Homop'tera the anterior wings are not thick- 

 ened, but are of the same structure throughout, as in the cicada. 

 In the sub-order Parasl'ta are found wingless parasitic hemip- 

 tera which prey upon certain mammals, for example, the head 

 and body lice of man, dogs, cattle, hogs, sheep, mice, and 

 rabbits. 



1 See Kellogg, p. 164. 



