590 NOTONECTINA. 



great variation from JV. maculata ; but when expanded, the latter (in 

 all examples I have seen) shows a reddish colour on the body, 

 which I never saw in glauca or furcata, and I have never seen one I 

 could not at once decide on." 



FAMILY 2. PLEID^E. 



Genus 1. PLEA, Leach. 



Ovate, very convex longitudinally, posteriorly compressed laterally; 

 the whole upper surface covered with punctures, and appressed 

 intermediate hairs. 



Head scutellate, large, convex, curved under in front, slightly wider 

 across the eyes than the front of the pronotum ; viewed from the 

 front, including the eyes, triangular. Antenna 4-jointed ; 1st joint 

 curved ; 2nd subcylindrical, both very short ; 3rd broad, fusiform, 

 twice as long as^the 2nd ; 4th small, clavate, inserted obliquely below 

 the apex of the 3rd ; the 2nd and 3rd internally, the 4th towards 

 the apex, pilose. Eyes remote, sub triangular, flat-convex, slightly 

 prominent, trenching on the anterior angles of the pronotum. 

 Rostrum sbort, 1st joint annular, nearly covered by the labrum and 

 the cheeks ; 2nd and 3rd obconic, 3rd shortest. 



Thorax. Pronotum convex, transverse, obscurely hexagonal, 

 hinder sides long ; posterior margin, across the scutellurn, slightly 

 sinuate. Scutellum large, triangular. Elytra subrhomboidal, apex 

 entire ; Clavus broad, with parallel sides ; Corium ; anterior margin 

 narrow, linear, inwardly with a parallel depressed line ; the posterior 

 margin of each elytron meeting in a straight longitudinal line ; 

 Embolium small, linear, on the anterior angle of the corium ; Mem- 

 Irane wanting. Wings ample, laid in several folds, with 1 cell at the 

 base, near the anterior margin. Sternum; the deep sockets of the 

 coxa? only separated from each other by thin, vertical plates, the 

 segments otherwise only visible at the sides as triangular plates. 

 Legs ; all of like form, 3rd pair longest ; coxa large ; fulcra ; 3rd 

 pair stout, elongated, and angularly bent ; thighs reversed- clavate ; 

 tibice almost trigonal, 3rd pair finely ciliated ; tarsi, 3rd pair longest ; 

 1st joint very short, 2nd and 3rd subequal, except in the 3rd pair, 

 where the 3rd is longest ; claws stout, short. 



Abdomen beneath with a middle row of small spines. The Genital 

 segments appear to follow the same type as in Notonecta. 



Like Notonecta, Plea swims with the back downwards. 



