HEMIPTERA. 



129 



composed of two pieces joined together at their sides ; one of these 

 is narrow, and is the part next to the scutellum when the wings are- 

 closed (Fig. 113, CI) ; this is distinguished as the cldvus: 

 the other broader part is the corium (Fig. 113, Co). 

 The terminal portion of the wing-cover is designated 

 as the membrane (Fig. 113, J/). In certain families, a f,,. ii 3 .— 



, . . , r , . . Diagram of 



triangular portion of the terminal part of the corium is wing-cover. 

 separated as a distinct piece (Fig. 113, Cu) ; this is the 

 cuneus. In certain other cases, a narrow piece on the costal mar- 

 gin of the corium is separated (Fig. 113, E) ; this is the embolium. 

 Both pairs of wings in the Homoptera and Heteroptera are furnished 

 with veins ; but it is not necessary for the purposes of this work to 

 discuss here the nomenclature of these veins. 



The mouth-parts are formed for piercing and sucking. Without 

 dissection, they usually appear as a slender jointed beak, arising at 

 the base of a shorter pointed labrum. This beak consists of four 

 bristles inclosed in a fleshy, jointed sheath (Fig. 114). 

 Two of the bristles represent the mandibles, and two 

 the maxillae. The sheath is supposed to consist of the 

 labium and the grown-together labial palpi. This sheath 

 is usually four-jointed, and is never composed of more 

 than that number of segments. The maxillary palpi 

 are wanting. 



Most of the Heteroptera protect themselves by the 

 emission of a disagreeable odor. This is caused by a 

 fluid which is excreted through two openings, one on 

 each side of the ventral aspect of the thorax, behind or 

 near the middle coxa. These openings are termed 

 '' a.' • u I4_ the osteoles. Each of these is usually in some kind of 



Mouth- parts J 



°ir'Muhr') U " an °P en channel styled the osteolar canal, and this is 

 surrounded by a more or less rugged and granulated 

 space, the evaporating surface. The legs of the Hemiptera vary 

 greatly in form, but the tarsi are never more than three-jointed. 



The lateral margin of the abdominal segments is much devel- 

 oped in several families, and forms a flat, reflexed or vertical border 

 to the abdomen, which is called the connexlvum. 



In their transformations the Hemiptera pass through an incom- 

 plete metamorphosis. The rudimentary wings of the nymphs lie 

 in the normal position, with the lower side of the wing next to the 

 body, and not inverted as with the Jumping Orthoptera. The 



