Caddis flies in the Leptoceridae, Rhyacophilidae, Hydropsychidae, Polycentropodidae, Philopotamidae, Odontoceridae and Molannidae Families

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Featured caddis fly families

Phryganeidae Limnephilidae Phryganidae Molannidae
Leptoceridae Rhyacophilidae Hydropsychidae Polycentropodidae
Philopotamidae Odontoceridae    
Triaenodes sp. caddis fly case

Leptoceridae family, Long-horned caddis

The females in this family lay eggs in a jelly mass on stones and plants. The larval cases (see Trianodes sp. left) are relatively narrow and some are slightly curved. They tend to be made of plant material or sand grains. Most of the larvae are vegetarian. The adults have very long antennae; sometimes 3 times as long as the body. There are 31 British species.

On the left is Triaenodes sp., its case is similar to those in the Phryganidae family. It is

Leptocercus sp. adult caddis fly

20 30 mm long, and made of plant material arranged in a spiral. The larva is an active swimmer, and its 3rd. pair of legs are very long and covered in hairs. Before it pupates the larva fixes the case to a plant. The eggs are found on the undersides of floating leaves.

Larvae in the genus Leptocercus (left) have a curved case usually made of sand grains and 11 - 17 mm long.

Rhyacophilidae family

The eggs are stuck to the bottom of stones in streams. The larvae (right) are actively predaceous carnivorous, and found in rapidly-flowing water. Not all species in this family construct cases, and the ones of those who do tend to be rather simple and crude. There are 90 European and 4 British species.

Rhyacophila sp. larvae (right) are found on the under surface of stones and fast-flowing water. They do no build a case. Fully grown larvae are 9 - 14 mm long and are green and brown. They move around quite quickly using their legs and anal appendages to hold on to stones to avoid being swept away. The larvae pupate in the late autumn in a shelter they make of small stones stuck to the underside of a larger stone. Inside this is makes a cocoon.

Rhyacophilia sp. caddis fly larva

Hydropsychidae family, Grey Flags, Marbled Sedges

In this family the larvae and eggs are found in fast-flowing streams. The eggs are cemented to the underside of stones. There are 60 European and 11 British species.

The larvae (see Hydropsyche sp. right), are very active, and when fully grown can be 10 - 20 mm long. Very young larvae do not have gills. Note that the anal appendages are large. They do not build a case, but live in a silk net stuck to the underside of a stone. The silk to make the net issues from oral glands. Inside the net there is a silk tunnel, open at the end which faces the flow of water, and closed at the other end. The larva lives in the tunnel and eats anything - animal or vegetable - that is caught in the net.

Before pupating the larva constructs a shelter made of small stones.

Adults swarm in the evening prior to mating.

Hydropscyche caddis fly larva
Polycentropus caddis fly larva

Polycentropidae family

The larvae, (see Polycentropus sp. on the left) are carnivorous web spinners with no abdominal gills, but 5 anal gills. They have large anal appendages with terminal hooks. They live inside a silk web and do not construct a case. They are found in all types of water except fast flowing. There are 13 British species.

On the left is Polycentropus sp. a fully grown larva is about 12 mm long. They are found in rivers and lake edges, and are sometimes found in groups.

The Philopotamidae family

The larvae have orange or yellow-brown, narrow heads. In this family the larvae catch their food (mainly diatoms and detritus) in long, tubular bag-nets which have a very fine mesh. There are 5 British species.

On the right is Philopotamus sp.

Philopotamus sp. larva

Limnephilidae family.

The Limnephiliidae have 55 U. K. species; more than any other family. Many of the species are difficult to identify, but some can be identified from the structure of the larval case.

The larvae make their cases out of a variety of materials. They are found in stagnant or slow- moving water. Quite often the case is so heavy that the larva cannot swim, but only crawls around. The total length on the case on the right is about 15 mm.

Limnephilidae larva, caddis fly larva
Odontocerum albicorne nymph

Odontoceridae family .

On the left is Odontocerum albicorne, also known as the Silver sedge . It makes its nest out of grains of sand, and is found in fast flowing bouldery rivers. There is just one British species in this family.

Adults have a wing length of 13 - 18 mm, and the antennae are longer than the fore wing. Adults fly from June - September in the afternoon and evening.

Molannidae family

Below is an adult in the Molannidae family. The larvae live in still water of lakes and large ponds and construct their case out of sand grains, see the drawing on the right. The case is a central, tapering cylinder covered by a broad, almond-shaped shield. There are only 2 British species in this family.

adult caddis fly in the Molannidae family

caddis fly case of Molanidae

Molanna angustata

On the right is Molanna angustata. It is fairly widespread.

The adult has long hind legs and an forewing 10 - 12 mm long. The antennae are longer than the wings. The adults are seen from May - September.

The larva is found in sandy-bottomed lakes and slow rivers and streams.

Molanna angustata