{{start}}

This definition covers insects from two separate orders. The first are the aquatic bugs of the hemipterus order and the second the aquatic beetles of the order coleopteran.

Water boatman and back swimmers

Whilst there are over 5000 different species of aquatic bugs Australia only two are of significance to the fly fisherman.
The family corixidae, more commonly known as corixia or water boatman come in a variety of shapes but all generally consist of a body between 5 and 10mm in length. They have two sets of wings with the font wings presenting almost as legs and the rear wings often trailing behind almost as rudders and the body is a relatively flat beetle shape (3 :1). The insect is a free swimming but seldom moves far from cover. They inhabit sluggish streams and still water and they are generally dark in colour. They are air breathers and swim to the surface from time to time an trap an air bubble which they hold under their abdomen.

The second aquatic bug of interest to fly fishers is the back swimmers or the family ntonectidae. Their general shape and habits are similar to the corixidae family and they are not generally distinguished between when it comes to representing them with an artificial fly. Having said that they are a little slimmer and their colours are a little more varied ranging from shades of olive, thought to dark khaki and brown.

Aquatic beetles

There are over 28,000 species of aquatic beetles in Australia and most of these are probably targeted by trout or other fish from time to time.

Having said that fly fishers have generally not focused on tying  any flies to represent either the lava or adult of individual species of these aquatic or water beetles.  This is probably because other than by detailed autopsy it is difficult to identify if trout are feeding on juvenile or adult water beetles as apposed to say nymphs of other insects or drowned terrestrial beetles.

Because this identification is so difficult for the fly fisherman (and hopefully the trout) it is assumed that trout feeding on lava of water beetles will accept nymphs of other insects and trout feeding on adult water beetles will accept a drowned beetle representation such as a red tag or a cock-y-bonddu or in the case of diver beetles a corixidae representation.

Aquatic beetles

This is an area worthy of a lot of further consideration.

{{end}}