of this group easy to recognize. The cases vary widely in shape and in the material used to create them. Some are finely constructed of sand grain or gravel, while others like broken bits of leaves or twigs. Most genera of tube case caddis can be recognized simply by the type of case they build. Cased caddis vary widely in size, ranging from 1/4'' inch to over 2'' inches. Typical cases are are a dark brown color. Colors of the larvae are typically lime green, brown, dark green, and yellow with the head and thorax being black.
Most larvae reach maturity in six to eight months, at which time they attach their case to rocks, plant life, or submerged tree branches, and seal both ends and transform into a pupa. The pupae are well protected inside the larval case and require between two weeks to over three months to fully mature.
Because pupa family identification
is difficult, the fly fishers main concern should be the insect's size and
color. 
The
major pupal colors are shades of yellow, brown, green, and gray. To determine
the pupa's color is best done by opening a sealed case and removing the pupa.
If the pupa's wing pads are dark brown or black the pupa is close to maturity.
Pupas will typically range from 1/4" inch to 1 1/2" inches in length.
Importance:
Fly fishers should not overlook all the stages of tube case caddis, because fish don't. Fish will feed on larvae, cases and all. The American Grannom of the Brachycentridae family is a cased caddis species that drift in rivers in very high numbers. This makes them readily available to fish. The Cased Caddis or CM's Peeking Caddis are great imitations when there is an abundant amount of cases floating down the river or stream.
The pupa stage is the most important stage to imitate by fly fishers. The pupa stage consists of the pupa leaving its case and swimming to the surface to emerge. Once the pupa arrives at the surface the pupal skin splits open quickly, allowing the adult to escape. Emergence is a very fast process and adults are typically not available to feeding trout. Because of the quick flight of caddis, the emerging pupal stage becomes the main target for feeding trout during a hatch. Typically emergence occurs in the evening and after dark.
Once the adult has safely taken flight, they will head for the foliage near the river or stream and begin the mating process. The adults will then return to the water to lay their eggs. Most tube case adults will lay their eggs on the surface of the water by skating along the surface and dipping their abdomen in slow to moderate currents near the shore. When the adults do come back to lay their eggs, fishing a dry fly caddis pattern dead drift or with a skating action can result in some great fishing.
Major families:
There are two major families which are of most importance to fly fishers. First, there is the Brachycentridae also known as the American Grannom. Typically these case making caddis are found in faster water. Their finely constructed cases are often attached to the upper surfaces of rocks in riffles and runs. They are also found in large numbers in moss, algae, or rooted plants growing in fast to moderate currents. Emergence usually occurs in fast to moderate water as well. The cases that are constructed are mostly rectangular or round tapered.
The second major family are the Lepidostomatidae, also known as the Little Plain Brown Sedge. These case making caddis are mostly found in backwaters, pools, or slow moving waters near the shore. Most Lepidostomatids often move to slower water to pupate. Their constructed cases are tubular sand grain or rectangular chimney-shaped. The major visible larval difference from the Brachycentridae is that the Lepidostomas have a lateral hump near the legs. You've got to have a good pair of eyes to detect this difference.
Other families include Oligophlebodes (Little Western Dark Sedge) and Limnephilidae (Summer Flier Sedge).
During their development the larvae of both families are relatively slow moving and inactive. They are unable to swim. If washed off the bottom they drift with the current until the bottom can be grasped. Insect drift studies have shown that large numbers of Brachycentrids are common in the drift which make them readily available to feeding trout. The descriptions for Brachycentrid and Lepidostomatid adults are identical, which consist of a tan or brown body with gray wings, about a hook size 16.
Flies:
Larvae: Herl Nymph, Peeking Caddis, CM's Peeking Caddis, Gold Ribbed Hare's Ear
Pupae: Deep Sparkle Pupa-tan, Deep Sparkle Pupa Emerger-tan, Soft Hackles-tan and gray
Adults: Elk Hair Caddis-gray, X-Caddis-gray
Major Hatch Periods:
American Grannom: April 25 - June 15
Little Plain Brown Sedge: June - August
Little Western Dark Sedge: June - August
Summer Flier Sedge: June - October