350 NATURAL HISTORY OF AQUATIC INSECTS CH. 



Fig. 104. — 6, advanced larva of Gerris sp with wing-cases and incomplete abdomen ; 

 7, larva, probably of wingless form ; 8, abdomen of half- winged imago ; 9. fore 

 tarsus, two-jointed ; 10, 11. extremities of lancets ; 12, inner pair of do., inter- 

 locking and forming a tube. 



