Various small zygopterans, such as e.g. many Cercion species, that hardly ever fly more than an inch above the water surface, are extremely difficult to net in the air. In southern and southeastern Asia we have often caught them by covering them with the net over the water surface, and then pulling it through the water. Though this technique is fairly efficient, it has the disadvantage that it is applicable only in fairly deep water with little or no surface vegetation; the frame of the net has to be rather strong, and the specimens collected in this way, as well as the net, are wet. Hence, in order to keep the triangles (envelopes) dry, a second person is required to envelope them with dry hands. During our 1980 collecting trip in Taiwan, where we have been guests of our friend, the well-known Taiwanese odonatologist Dr J.C. LIEN (Medical Entomology Section, Taiwan Provincial Insitute of Infectious Diseases, 161 Kun-yang Str., Nankang, Taipei, Taiwan), we have learned from him to collect by means of an aspirator. The aspirator method, developed and used by Dr Lien, is very simple and extremely efficient. Such species as eg. Cercion calamorum, etc. that fly close to the water surface among thick aquatic vegetation (e g. water lilies) can hardly be collected by netting, while long series can easily be acquired by aspirator within the shortest thinkable time.