Terrestrials refers to all of the non-aquatic insects which are of interest to trout fishermen. Essentially they become part of the trout's diet because their presence in the water is sufficient for the trout to recognize them as food even though their presence is opportunistic and not readily predictible. For our purposes the term refers to ants, hoppers, crickets, cicadas and beetles which might readily fall into the water and become food for the feeding trout. However the term will also cover other insects such as bees, wasps, moths, butterflies and any other insects which fall into the water.
We have prepared some notes on ants, hoppers and beetles which might be of interest.