The ability to absorb solutions has been examined in the coxal vesicles of the ventral tube in two sympatric surface dwelling Collembola ( Tomocerus sp. and Orchesella villosa) from a beech forest. The net influx of distilled water and different sodium chloride solutions was measured, followed by examination of the effective surface of the vesicles which contacts the medium. The transport rate decreased with increasing salinity of the medium. Orchesella always showed higher absorption rates than Tomocerus, if the values were related to unit surface area. However, considering that the effective surface area of the vesicles of Tomocerus is larger, the total absorption rate by the ventral tube of Tomocerus exceeded that of Orchesella. Calculating the increase in the total water content. Orchesella compensated for its deficit faster than Tomocerus, because Orchesella is smaller in total weight and water content. In most cases the efficiency of the absorptive epithelium decreased during an absorption cycle; this also occurred before moulting. Some hours after moulting, the absorption rates increased to their former level. Comparing the rates of transpiration, absorption by the ventral-tube vesicles, and drinking, confirmed the dominant role of the ventral tube in the water balance of Collembola. It is an important factor in the strategy of adaptation from the hypogaic to the epigaic life.