Abstract
By micro-chloride determinations combined with other observations, it is shown that Chironomus and Culex larvae are able to take up chloride parenterally from solutions with a chloride content corresponding to that of ordinary fresh water. This active absorption takes place exclusively in the anal papillae (anal gills). Since, in Chironomus, salt diffuses continually through the whole body surface, these organs, by their salt-absorbing function, play an important part in maintaining the salt content of the body fluid.