Many attempts have been made to overcome the difficulties attendant upon storing insect material over extended periods of time in small vials of alcohol. Cork stoppers fail to meet requirements for various reasons, while their substitution with rubber ones may introduce still further complications. Both are liable to shrink or to swell while either may be forced out of the vials as a result of variations in room temperature. In addition, neither can be readily marked in such a manner that the contents of the vials are permanently and plainly legible from above.