NOTONECTINA. 585 



Length (exclusive of spiracular filaments), 7 — 10 lines ; filaments 

 4 lines. 



Common in and on the mnd of stagnant water, throughout the year. 



Section 4..—N0T0NECTINA.^ 

 Family L— NOTONECTIDyE. 



Genus 1. — Notonecta, Liu. 



Long-oval, semi-cylindrical ; membrane of the elytra folded longitu- 

 dinally, saddle-formed. 



Head transverse, including the eyes almost reniform, rounded in 

 front and curved completely under. Antenna short; 1st joint short, 

 stout, truncate-conic ; 2nd stout, subcylindrical, constricted at the 

 base ; 3rd narrower, nearly as long as the 2nd, thickened on one side, 

 with prominent, fine, capitate hairs ; 4th short, thin, conical. Eyes 

 very large, long-triangular, curved with the head, posteriorly 

 broadest, viewed from above set obliquely, the interior part of the 

 base of each set forward and approximating to the other, their pos- 

 terior margin trenching on the anterior angles of the pronotum. 

 Bostnim reaching to the mesosternum, stout, curved, conical; 1st 

 joint short, covered by the labrum ; 2nd shorter than the 1st, con- 

 stricted at the base, with a tuft of hairs on each side ; 3rd as Ions: 

 as the 1st and 2nd together; 4th conic, as long as the 2nd ; lahrum 

 large, triangular, pointed. 



Tliorax. — Pronotum convex, irregularly 6-sided ; anterior margin 

 a little shorter than the breadth of the head, including the eyes ; 

 sides long, divergent ; hinder sides short, merging into the posterior 

 margin, which is slightly concave. ScuteUuin convex, long, trian- 

 gular, with a long point, the posterior -i sunk into the metanotum ; 

 Mctanotum long. Elytra; Claviis long, trigonal, the sutural side 

 longest ; Corium ; anterior margin at the base very narrowly reflexed, 

 posteriorly sinuate ; posterior margin indicated by an oblique raised 

 line extending from the inner margin but not reaching the anterior 

 margin ; the JSIemhrane beyond this, but exterior to the longitudinal 

 fold, at first of the same' substance as the corium, then gradually 

 thinner, interior to the fold it is entirely thinner, with a distinct, 

 narrow, flattened margin ; the apex with a deep angular notch on 



* Page 47. 



