See this Washington Post article:
Mechanical engineer David Hu and a team of colleagues at Georgia Tech were pondering a mosquito's ability to take a direct hit from a falling raindrop uninjured. Following is a quote from the article:
That sort of reasoning would be like arguing that a 10000-lb truck striking a pedestrian would pack a lesser wallop than a 250-lb linebacker at the same speed, which we know not to be the case. The mosquito can take a sudden impact-induced velocity change that would be hard on a human because, like any small creature, it has the strength to mass ratio in its favor. If the body tissues are similar, the stress-bearing strength of the whole body is proportional to the square of the linear size, while the mass is proportional to the cube.Hu and his colleagues hypothesized that due to the insectsí low mass ó about two milligrams, compared with a raindropís mass of up to 100 milligrams ó the raindrop loses very little speed and momentum upon encountering the mosquito and thus imparts very little actual force to it.
It's a shame when professional scientists and engineers have such lapses in entry-level physics, or when ill-informed writers misquote them.