Listers -

This is a very interesting discussion, and one that has a lot of relevance for our lab. Our collection is small and mostly devoted to limited series that we use frequently as reference specimens for identification services. We stopped making permanent slide mounts well before I began working here, instead making temporary mounts, photographing them, and then storing those genitalia in glass vials with neoprene stoppers on the same pin as the rest of the specimen. 

Typically this serves our purposes well. We can use our digital library to efficiently compare several species simultaneously on one screen, and have the option to remount and re-photograph specimens if we find we didn’t quite capture the correct features.

This saves us time and money, and we have only one physical collection to manage (rather than a slide collection and a mounted specimen collection). My questions to the forum are:

What is it about vial-stored genitalia that increases the likelihood of disassociated specimens vs permanent slide mounts. Is it simply that slides are labeled with the specimen info, while the vials must be kept on the pin with the label, or is there another aspect to this that I am missing?

Has anyone heard about Euparal eventually resulting in overly cleared specimens? My predecessor maintained that he had heard this, and that some older specimens were so cleared that they could barely be seen. Is this real, or a misinterpretation of someone's anecdote? If real, was it a failure to properly clean the mount or does Euparal really clear specimens over time?

Thanks again for the scintillating discussion!


Chris Looney, PhD
Entomology Laboratory
Washington State Department of Agriculture
1111 Washington St. SE
Olympia, WA 98504
Desk: 360.902.2042
Lab: 360.902.2084

-----Original Message-----
From: Entomological Collections Network Listserve [mailto:[log in to unmask]] On Behalf Of Solis, Alma
Sent: Wednesday, July 18, 2018 12:02 PM
To: [log in to unmask]
Subject: Re: glycerol (and adhesive follow-up)

In the early 1990's I reconstituted genitalia dissections of Walker type specimens by Tams at the NMH London from more than 70 years prior that were stored in vials that were presumably dried out.
The vial held some "gunk" at the bottom and a little paper label and that's it, no cover to the vial.
I was pleasantly surprised that the genitalia was still intact.

This was slightly different from slides made with glycerin and let to dry that I found at the CNC Ottawa.
Not much work in reconstituting, but the whole thing was dried out and parts missing because the cover slips were just "sitting" on top of the structures.
When the genitalia was present it was complete (soft bits not disintegrated).

The danger is not in the glycerine in vials in my opinion, but how the vial is stored in relation to the specimen.
It increases the possibility of NOT being able to match the dissection to the adult. I was unable to physically match other Tams dissections to adults.
And of course, the concept of glycerine slides for long term storage should not be done (I would guess unless it is sealed with an adhesive).


Dr. M. Alma Solis
Research Entomologist
SEL, USDA, Smithsonian Institution
P.O. Box 37012
National Museum Natural History, E-517, MRC 168
Washington, DC 20013-7012
Phone: 202-633-4573
E-mail: [log in to unmask]

-----Original Message-----
From: Entomological Collections Network Listserve [mailto:[log in to unmask]] On Behalf Of Andy Deans
Sent: Wednesday, July 18, 2018 2:28 PM
To: [log in to unmask]
Subject: glycerol (and adhesive follow-up)

Hi all,

Does anyone know the history of glycerol / glycerin / glycerine use in entomology, for storing genitalia, etc.? I see references from the 1950s at least, some with additives like chloral hydrate and (yikes!) arsenic. Does anyone know how stable glycerol alone is over the long term? I heard anecdotally that there are specimens more than 100 years old that have been stored in glycerol. My impression is that these older specimens are mostly cuticle - the soft bits having been digested away with KOH. Would soft tissues preserve well in glycerol alone? Thanks for any help!

Also, thanks for your responses to the survey about adhesives. I have been researching different classes of adhesives and now have a manuscript to be shared shortly. The results will also be presented at the meeting in Vancouver. More soon ... but I should put at least this advise out there now: We really should stop using clear nail polish and Elmer's! They are NOT archival.

Andy Deans
Frost Entomological Museum
Penn State

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