CtASS V. IN3ECTA. 227 



Inhabits Kngland, near Bristol, Plymouth, and Exeter. 

 Elytra with the apex of a palish black. 



Sp. 3. Not. glaucn. Elytra grayish, the margin with minute blackish 



spots : back black, the apex pale brownish. {PL 5. fg. 3.) 

 Notonecta glauca of authoi's. 

 Inhabits Britain in almost every pond. 



Genus 290. PLEA. Leach, Trans, of Linn. Sac. vol. xii. 



Bodi/ of a squarish oval: antennae with the third and remainder of the 

 joints largest : anlei'ior /«r.s7'with the articulations nearly equal: cluw9 

 on the hinder feet large. 



The thorax is obscurely hexagonal with the hinder margin prominent 

 and rounded, the heud as broad as the broadest part of the thorax: 

 the eyes are rather oblong, without the least tendency to converge 

 behind : the hinder pair of legs not more ciliated than the others, but 

 are terminated by very strong and distinct claws : tips of the elytra 

 acuminated and entire. 



Sp. 1. Not. mmufissima. Gray with a brownish line in the front: thorax 

 and elytra deeply punctured. 



Notonecta tfinerea, anelytra. Geoff. Ins. Par. i. 477. 2. Notonecta 

 minutissima. Fourc, Latr., Oliv., Fair. Plea minutissima. Leach, 



Length of the body 1^ lin. 



Inhabits ponds and stagnant waters near London in profusion. 



" This species has been considered by GcofFroy, Fabricius and Oli- 

 vier, as Notonecta minutissima of Linne, which reference imdoubt- 

 edly belongs to the following species ; viz. to Sigara minutissima." 



" GeofFroy has described the larvse, never having seen the perfect 

 insect." 



Stirps 2. — Bodi/ roundish and depressed: tarsi, the anterior with one 

 articulation ; the hinder with two ■■, base and margin of the elytra 

 only channelled. 



Genus 291. SIGARA. J^ach, Trans. Linn. Soc. vol. xii. 



Scutellum distinct : thorax divided by a transverse line : bodi/ ovate, the 



posterior part acuminated. 

 Sp. 1. Sig. minutissima. Above cinereous: elytra brovmish with very 



faint spots ; the under part and feet yellowish. 

 Notonecta minutissima. Linne. Sigara minutissima. Leach. 

 Inhabits rivers and running waters in England, Ireland, and Scotland. 

 Len2;th of the bodv 1 lin. 



Genus 292. CORIXA. Geoffroij, Leach. 

 Scutellum none : thorax transverse, the posterior part produced : lodi^ 

 long, the anterior and posterior part rounded. 



" The thorax is more or less produced behind in all the species of 

 this genus, but is not evident in the first division of thi? genus until 



p 2 



