/ chaptp:r v. 



ORDER HEMIPTERA. 



The Ilemiptera constitutes one of the large orders of 

 insects and includes some of the very important economic 

 species, and some of the very striking specializations in 

 insect life history including extremes in different kinds of 

 environment, life habit, and one of the most striking extremes 

 in the matter of reproduction and de\'elopment. 



The essential character of the order is found in tlie devel- 

 opment of the mouth parts, there being also other distinct 

 differences in the matter of wing structure and some other 

 parts of the body. The mouth parts are adapted for suction 

 in the larval as well as the adult stages. This represents a 

 more radical change of these parts than when the mouth 

 parts are different in different stages. The modification 

 in the mouth parts consists in the change of the mandibles 

 and maxillse into bristles or setse which serve to puncture 

 the tissues of the plants upon which the insects feed by 

 l)umping out the juices. The labrum (epipharynx of some 

 autliors) is present as a rather aborted structure; the labium 

 is modified into a sheath for the bristles or setse and is usually 

 three- or four-jointed. These segments are fitted together 

 to form a sheath or tubular or furrowed organ within wliich 

 the bristles or sette play back and forth as they are dri\en 

 into the tissues which constitute the food of the insects. 

 Within the group there are differences in wing structure 

 which enable us to separate the group into two very distinct 

 suborders, and in some cases three are recognized, the third 

 including only parasitic forms. 



The two main suborders are tlie ITomoptera and the 

 TIeteroptera, the first including those forms which ha\e 



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