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Caddis flies are also known in some cases as sedge because of their habit of clinging to vegetation, particularly sedge type grasses, along the banks of rivers and impoundments. Whilst caddis appear on general inspection to only have one pair of wings they in fact have two pairs of wings but the second pair is only slightly forward of the other. The wings basically present as a V shape fixed by the apex in front of the thorax with the wing getting gradually wider as it laying along the sides of the insect and toward the back of the fly. They don't have tails but they often have long antenna.

Caddis fly (or Sedge) are of the order Trichoptera (Greek for 'hair wing') and are common from September through to January particularly in the flooded margins of lakes. They are a substantial part of the trout's diet. Some say as much as 70%.  Like the mayfly in the sketch below Caddis Flies pass through four stages in their development; egg, larva, pupa and adult.

Whilst stick caddis and sand caddis are well known to fly fishers there are many other types of cased caddis on the trouts menu.

The eggs germinate in jelly masses that are generally attached to shore based vegetation but in some species Caddis lay their eggs directly on vegetation.

The eggs have a gestation period of only around 10-12 days after which, depending on the Genus, they hatch into one of three different forms of caddis pupa:

• Some caddis hatch as free swimming pupa living in or close to detritus matter and vegetation. These caddis are constantly vulnerable to feeding trout, particularly when they leave the flimsy protection of detritus matter and vegetation and swim to the surface to emerge.
• The second group of caddis secrete a silk like substance which they use to build retreats that they fix to vegetation only leaving the vegetation when its time to emerge.
• The final group immediately after hatching into pupa secrete a sticky substance which attaches to material in the water to become case which they live. These are the cased caddis and depending on the Genus there cases can be constructed of various forms of particulate matter including: sand, twigs, leaves or other detritus matter. These cases provide the pupa with a camouflaged habitat and a little security. They live in their cases for a few days going through a number of instars and after each instar they add additional particulate matter to their protective camouflage cases. Whilst in these cases the pupa can poke their tiny head and shoulders out of the camouflage case to feed and move around. From a fly fishers point of view the most important So called stick caddis are particularly vulnerable as they shed their skins during an instars, when they have their head outside the case feeding and of course when they leave their cased homes to swim to the surface to emerge.

What ever their pupal form when it is time to emerge they leave their relative safety of their, habitat, silk or particulate retreat and using tiny middle legs swim to the surface, shedding their nest and shuck as they breaks through the surface tension of the water so as to reveal their wings. Caddis flies often use surface movement caused by wind and currents to assist in this process. Fortunately they break through the surface quickly. The surface in some cases is amongst vegetation where they are popular food for "tailing trout" but in other cases that is in open water where they are easy prey for a short time. Some times they appear to be able to fly straight away without waiting more than a moment for their wings to dry and often you will see trout “porpoise” out of the water to take these quickly emerging Caddis flies. Other times they break through the surface and unable to fly make a dash for the bank and cover, skating across the surface creating a a tell tail wake that trout home in on. Often you will find that the timing of a hatch a coincide with warmer evenings with just a little breeze. These conditions help the nymph shed their nest and shuck and allow the wings to dry quickly.

The Caddis fly spends its adult imago life as a terrestrial insect and finally returns to the water. The male fertilises the female above the water and around water side vegetation  and then the females’ dance on the surface of the water, or around vegetation close to the water, on mass and then lay individual eggs on the water that quickly sink to the bottom or on vegetation close to water. In either case this is a real turn on for trout and you will often find large numbers of fish aggressive feeding on both the water egg laying female Caddis fly as well as spent adults of water laying females and vegetation laying females.

The colour range of the emerging caddis are relatively drab but they are generally in shades of brown, gray or green. Hatches generally occur an hour or so after dawn and before dusk but some species do hatch throughout the day.When hatches occur fish often become very selective and fixated on caddis a food source ignoring all other offerings.

The terrestrial insect like the pupa and nymph vary in size from the tiny snow flake caddis of just 3-5 mm in length to  larger long thin moth like beasts that may be up to 25 mm in length..

Caddis lay they eggs and as well as being vulnerable to trout when going through their instars, and when they have their head an shoulders outside their camouflage case they are very vulnerable as they lay their eggs.

The eggs that are laid in the open water form into floating jelly masses and drift around until by chance they stick to vegetation that the eggs drift through and past . . . and hence the cycle starts again.

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