Vials with Ethanol

Author: Pat Wooden
Mississippi Entomological Museum, Mississippi State University, MS 39762
Uploaded March 10, 2026

Immature aquatic insects are stored in ethanol long-term, as they are too membranous for pinning. Whether adults are pinned or kept in ethanol is up for debate. Many keep all
aquatics in ethanol for consistency in teaching and storage – ethanol collections have very different maintenance than pinned ones, and many want to only have to think about one set of challenges.

70% ethanol is preferred unless DNA work is desired. Many characters are inside of the mouth or between leg segments, and specimens in a lower concentration of ethanol are less brittle and easier to work with for fine identification. Collect directly into ethanol. These fluids should then be changed upon return from the field. Aquatic insects have a high concentration of water in their bodies, which dilutes preservative and can lead to rot.

A note on Megaloptera: Hellgrammites, fueled by spite and an incredible will to live, will eat everything you place in the vial with them. Keep them separate.