Simply pinning and spreading odonates like lepidopterans use to work fine, so why use cards and envelopes? The answer lies at the bottom of any museum's pinned odonate drawer: abdomens and heads, forever liberated from the thoraxes of the specimens. I initially felt uneasy about devoting the extra cost and space to odonate cards and their envelopes, but seeing the carnage that even gentle handling brings convinced me. Odonates are fragile creatures and my heart sinks a little whenever I pull out a drawer of pinned and broken specimens. While it's true that pinning them through the side and shingling them with the wings folded up saves significant space, this doesn't save them from the inevitable damage that handling causes.

If you're using my Filemaker database, then it's pretty easy. All you have to do is enter the normal info (locality, collector, fieldnumber, etc.), plus whatever taxonomic info you know, and put a unique value in the field "Arbitrary odonate series ID". That last part is for grouping that particular batch of odonates you want to make cards for when you search based on the field. My database will print four cards per 8.5"x11" sheet, and I recommend you print to PDF first to make sure it's looking right.

Just use cardstock like you're printing any other kind of labels, and print using the highest print quality and "Improve toner fixing" if your printer supports it. Cut the cards just within the black border to ensure they'll fit in the cards, and you're all set.