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XVIII. Revision of the Notonectide. Part I. Iniro- 
duction, and Systematic Revision of the genus 
Notonecta. By G. W. KirKxatpy. 
[Read Oct. 6th, 1897.] 
Tar genus Notonecta was erected by Linnzeus in 1758," 
and contained three species, N. glauca, N. striata, and 
N. minutissima. In 1762 Geoffroy? proposed the genus 
Corixa for N. striata, which, however, was not (or was 
only in small part) striata of Linneeus ; nevertheless the 
latter belongs to Geoffroy’s genus, and the type is there- 
fore limited to the two other origimal species. In 1794 
Fabricius® enlarged the scope* of his genus Sigara to 
admit a new species, minuta (= N. minutissima, L.), 
thus indirectly but actually establishing N. glauca as the 
type of the genus Nofonecta. In 1818 Leach published 
his ‘‘ Classification of Notonectides”’* with a new genus 
Plea {type Notonecta minutissima, Fourcr.), and in the 
following year, C. R. Sahlberg’s ‘‘ Observationes quasdam 
Historiam Notoneciidum .. . illustrantes,” appeared, in 
which Leach’s conclusions were closely followed. Spinola 
completed his “ Essai” in 1837, proposing two new genera, 
viz. :—Anisops for N. niveaand Hnithares for N. indica, L., 
anda new species, H. brasiliensis.6 In 1844 Fieber pub- 
lished his ‘‘ Entomologische Monographien,”” including a 
monograph (pp. 294-7) of the genus Ploa (Plea), and 
seven years later appeared his ‘ Rhynchotographieen ” ° 
upon pp. 469-486, of which (usually quoted from the 
separate copies, pp. 49-62) were described all the species 
known to him of the other genera, Bothronotus being 
arbitrarily substituted for Hnithares. Unfortunately the 
latter work has been rather a hindrance than a help, as 
the descriptions are not based upon structural characters, 
1 Syst. Nat. Iid., x., p. 439. ? Hist. abrég. Ins., i., p. 475. 
3 Ent. Syst., iv., p. 60. 4 Kirk., 1897, Ent., p. 260. 
Trans. Linn. Soc., xu., pp. 10-18. 
Jam not aware that any author has indicated a type for this 
genus, and therefore now set apart FH. indicu for that purpose. 
7 Abh. K. béhm. Ges. Wiss. (5) iii. 
S Abh. K. bohm. Ges, Wiss. (3) vii. 
TRANS. ENT. SOC. LOND. 1897.—pPaRT Iv. (DEC.) 
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