Freshwater aquatic hemipteran insects are often called ‘true bug’, belongs to the suborder Heteroptera. Scientists were in agreement that they were evolved in Triassic period of Mesozoic era. Although, they were secondarily adapted to aquatic life, their modified physio-morphological characters enable them to adjust in the new environment and help them to occupy almost all possible niches. Of all these changes, leg modifications showed promising effects. With modified leg structures, present day hemipteran bugs can walk, swim, grasp prey, able to escape from predators and lead a successful life. Present study deals with evaluation of lengthwise modifications of three pairs of legs of hemipteran bugs in relation to their niche. They were randomly collected from 3 different strata of lentic water bodies away from human interference and grouped them as surface feeders-rowers and walkers (Gerromorphans), underwater swimmers (Nicomorphines) and bottom dwellers (Leptopodomorphan). Each pairs of legs were measured and data were tabled separately. It has been observed that, different species of bugs belongs to the same family, when occupied different niche underwent modifications differently. Hence, bugs from quite unrelated taxa found to be assembled in the same area exhibited similar pattern of leg modifications. In other words, so far as evolutionary divergence is concerned niche selection gains priority for these aquatic bugs.