PARTHENOGENETIC ISCHNURA HASTATA (SAY), WIDESPREAD IN THE AZORES (ZYGOPTERA: COENAGRIONIDAE)

An apparatus for removing particles from a fluid stream includes an unobstructed channel for conveying a stream in turbulent flow and a series of objects extending at least along one side of the channel, the objects being closely spaced from each other in the direction of flow so as to define therebetween spaces in which eddies penetrate from the channel to cause collection of particles on surfaces of the objects upon decay of the eddies.