Good question. My responses are from my experience—I don’t know of papers on the subject.


Cons are mostly for folks working with the specimens. If your material does not have much traffic, it makes little difference. Personally, as one who works with lots of wet specimens (mostly aquatic insects), I dislike this storage, but can see why some would adopt it. Consequently, my list of cons is a little longer, others may weigh in with more pros.


Cons (some, may be others)

1.      loaning material is more difficult, sometimes collection managers will have to remove all in a bail jar to find the one you want

2.      prep time for loans is greater, need to be put in other storage for mailing

3.      Specialists visting the collection will likely be annoyed by the storage with this method of storage, it is slow, messy, and cumbersome to work through

4.      digitize the material is physically more difficult because the shell vials will leak during classic type, one-by-one transcription and catalog numbers will be harder to find afterwards

5.      gaskets for these also fail

6.      legs of specimens get tangled in cotton plugs

7.      you may find that you need many jars to separate out specimens, especially if you collection has lots of monotypic genera-just a guess

              Pros (some, others possible)

1.      I agree that this method certainly takes up less space

2.      Double container does minimize risk of seals failing for each shell vial and may reduce amount of evaporated ethanol in a collection space, but I can’t prove it.

3.      Specimens may be easily moved from one storage to another more easily than vial racks or vials in paper boxes

4.      This procedure would allow for more control on the ethanol concentration used

5.      All of us will have to eventually move specimens from patent lip/stoppered vials because there is not a source of high quality stoppers. The ones that are available harden quickly (Neoprene) or leave a red pigment in the alcohol (Latex) (if anyone offers you silicone ones, tell them no thanks—evaporation is problematic). Moving to 3 or 4 dram storage with caps having plastic liners is tedious and costly—but best solution in my opinion. Perhaps bail jars and shell vials are less costly and involve less handling for transfer.


Karen, if any of this is unclear—limited time to answer and lack of give and take—give me a ring.



R. Edward DeWalt

University of Illinois

Prairie Research Institute

Illinois Natural History Survey

1816 S Oak St.

Champaign, IL 61820

217-649-7414 cell

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Author of Plecoptera Species File



From: Entomological Collections Network Listserve [mailto:[log in to unmask]] On Behalf Of Karen Wright
Sent: Monday, June 05, 2017 6:26 PM
To: [log in to unmask]
Subject: bail top vs screw top


Hi everyone, would the EtOH folks please give me a pros and cons for screw top vs. bail top jars for use with shell vials. Thanks, Karen


Karen W Wright

Assistant Curator

Texas A&M University

Department of Entomology

2475 TAMU

College Station, TX 77843-2475