32, 33. Order Plecoptera (Stoneflies). Adults can be collected at lights or from stream side vegetation with a beating sheet or sweep net. Adults are best preserved in alcohol. Pinned adults can be very fragile and will often break. Because some adults are short lived, they may only be present for a few weeks. Naiads can be found on rocks or submerged plant material in well oxygenated portions of a stream. Select a riffle area of a clear stream and pull up rocks to which they cling for inspection. An aquatic net or Surber sampler may also be used. They should always be preserved in alcohol.