ABSTRACT
The lack of oxygen in the water is a problem that has to be overcome by any aquatic insect that must exist in water containing none at all, even only temporarily. Apparently, many species of Diptera developed very ingenious adaptations to overcome the problems of developing as larvae on or in polluted, oxygen-free water. Many of them belong to terrestrial families and live in various kinds of waste produced on farms and ranches, some of the waste almost dry and others drenched with water and fluid. Among the most remarkable of these belong to the family Syrphidae, some of which are aquatic as larvae and are not considered pests. The species are abundant in northern Germany, and these perform important functions in the terrestrial biotic communities. The region surveyed encompasses the Brazilian states of Amazonas, Para, Maranhao, and Roraima, which cover a vast forested area.
