348 NATURAL HISTORY OF AQUATIC INSECTS CH. 



FIG. 103. i, Gerris thoracica (the centre of the thorax should be paler) ; 2, wing- 

 less imago of Gerris najas ? ; 3, hind wing of G. thoracica ; 4, rostrum of 

 do. ; 5, transverse section of abdomen of G. najas. 



