Some species are serious pests to plant life, and swarm in countless thousands over vegetation, sucking up the sap and causing it to wither and die in consequence, as in the case of the Chinch Bug of North America upon wheat, and the Rutherglen Bug in Australia among field crops. Others are predaceous and very useful, destroying great numbers of leaf-eating grubs and caterpillars. These insects are well represented in Australia, and many of the larger and more showy ones were collected and described at a very early date, and their descriptions are scattered through the pages of many scientific journals. Numbers of our species have been described by Westwood (Hope Catal. 1837); Dallas (List Hemip. 1851); Walker (Catal. Heter. Brit. Museum 1867); Distant (Trans. Ent. Soc. London, 1886, etc.); Kirkaldy (The Entomologist); and others in English journals; while among the Continental writers Messrs. Stal, Bergroth, Montandon, Horvath, and Reuter have been the chief workers. In 1893 Messrs. Lethierry and Severin commenced a “Catalogue of the Described Heteroptera of the World”; three parts were published, but, probably owing to the death of Lethierry, it was never completed, part three closing with the ANTHOCORIDAE, and most of the aquatic groups are not listed. Dr. Mayr has in his “Monograph of the Belostomidae 1871” noted our species. [Illustration: Plate XXXI.--HEMIPTERA. Family PENTATOMIDAE. 1. _Biprorulas bibax_ (Bredden). 3. _Peltophora pedicellata_ (Kirby). 4. _Chaerocorus paganus_ (Fabr.). 7. _Plautia affinis_ (Dallas). 8. _Cuspicona simplex_ (Walk.). 10. _Dindymus versicolor_ (Herr. Sch.). 11. _Tectocoris lineola_ (Fabr.). 13. _Oncoscelis sulciventris_ (Stal.). Family PYRRHOCORIDAE. 2. _Dysdercus sidae_ (Montrz.). Family COREIDAE. 5. _Mictis profana_ (Fabr.). Family LYGAEIDAE. 6. _Oxycarenus luctuosus_ (Mont.). 12. _Oncopeltus quadriguttatus_ (Fabr.). 15. _Lygaeus hospes_ (Fabr.). Family REDUVIIDAE. 9. _Ptilocnemus femoralis_ (Horvath). Family TINGIDAE. 14. _Froggattia olivina_ (Horvath).] [Illustration: _Plate XXXI.--HEMIPTERA._] The Heteroptera have been divided into about twenty families, chiefly defined by the structure of the head and wings; these families are again subdivided into a great number of sub-families, many of the more important being represented in Australia. Family 1. Shield Bugs. PENTATOMIDAE.