IV. INSECTA: HEXAPODA, RHYNCUOTA. 489 



Order VIII. Rhynchota. 



The Khynchota, or bugs, in their external appearance are 

 nearest to the Archiptera and Orthoptera. The head, thorax, and 

 abdomen are joined in the same way; the development is hemi- 

 metabolous, and in the wingless species ametabolous. In some 

 cases, as the Cicadas with their membranous wings, the confusion 

 with the Orthoptera has led to these being called locusts; on the 

 other hand the delicate-winged Aphides resemble the Archiptera. 

 Yet all Rhynchota may be recognized by the sucking proboscis 

 (fig. 523), consisting of the grooved labium in which the needle- 

 like mandibles and maxillae play. The wing structures afford the 

 basis of division into three sub orders. 



Sub Order I. HEMIPTERA (Heteroptera). Anterior wings hemelytra, 

 i.e., leathery at the base, soft and elastic at the tip (fig. 524); between the 



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FIG. 524. Pentatoma rufipes. (From Hajek.) s, scutellum. 



hemelytra is a conspicuous triangular scutellum (s) which covers more or 

 less of the dorsal surface. Hemelytra and scutellum occasionally disap- 

 pear. A further characteristic is the presence of stink glands, producing 

 a most disgusting odor, which open in the adults ventrally on the rneta- 

 thorax; in the larvae dorsally on the abdomen. According to habits the 

 many families may be grouped into the aquatic HYDROCORES and the 

 terrestrial GEOCORES. Of the first the BELOSTOMHXE are noticeable from 

 their size, Belostoma americana* being nearly 2 inches long and capable 

 of inflicting severe wounds. Other families are NEPHXE (Ranatra, water 

 scorpion), NOTONECTID.E, HYDROBATIDJS, etc. Of the Geocores the REDU- 

 VIID.E, which feed on other insects; the ACANTHIIDJE (Acanthia lectuaria* 

 the bed bug); the LYGJEHXE, containing the chinch bug, Blissus leucop- 

 terus* so injurious to grain; and the PENTATOMID^E, or stink bugs, may be 

 mentioned. 



Sub Order II. HOMOPTERA, Wings, when not degenerate, similar in 

 texture throughout, although often differing in size. They are either parch- 

 ment-like or delicate membranes. The CICADID^, represented by Cicada 

 septendecim* the seventeen-year 'locust,' and C. tibicen* or dog-day har- 

 vest fly, are noticeable from their shrill notes, produced by a stridulating 

 drum on the abdomen. C. orni of the Old World fig. 526) punctures ash 

 trees, causing the flow of manna. The CERCOPID.E contains the spittle 

 bug (Apropliora *) which causes drops of foam on grass. The leaf hoppers, 



