Occasions frequently arise in entomological work when it is necessary to hold an insect absolutely still in order to operate upon it. A year ago an apparatus was devised for holding sawfly larvae for injection. It has now been improved and is being currently used to hold sawfly larvae quiet while substances are introduced into the midgut, The apparatus, shown in the accompanying figure, consists of a grooved plastic platform with small holes in the base. These holes are connected to a vacuum line. A water pump may be substituted very nicely. The larva can be placed in any position on the platform by lifting it on a stick and pressing it lightly over the holes on the platform. The larva can be freed immediately by releasing the vacuum. As long as the vacuum is regulated carefully, there are no harmful effects upon the larva.