Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin

Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

Stream photos

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Skwala (Large Springfly) Stonefly Nymph Skwala (Large Springfly) Stonefly Nymph

Dorsal view of a Skwala (Perlodidae) (Large Springfly) Stonefly Nymph from the Yakima River in Washington

This Skwala nymph still has a couple months left to go before hatching, but it's still a good representative of its species, which was extremely abundant in my sample for a stonefly of this size. It's obvious why the Yakima is known for its Skwala hatch.

6 Recently Added Photos

27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.

Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Caddisfly Family Glossosomatidae (Saddle-case Makers)

This family is one of the primitive caddisflies of the Rhyacophiloidea superfamily. However, they are not free-living like their better known cousins the Rhyacophilidae (Green Rockworm). Instead they build rounded "turtle" shaped cases that do not surround the larvae but are rather attached to the rock surface at their margins. Underneath is a sling made of secretions upon which the larvae ride, hence the common name Saddle-case Makers. There are four genera of possible interest but only one is generally recognized as important to anglers. See Glossosoma (Little Brown Short-horned Caddis) for details. The other three are so tiny that they are also called Pseudo-microcaddis.

Protoptila (Tiny Spotted Short-horned Caddis) is rarely important in trout streams and is generally found in warmer, larger water than the other two genera.

Agapetus (Tiny black Short-horned Caddis) is quite common in many northern streams.

Matrioptila is an extremely tiny southern genus.

Where & when

In 799 records from GBIF, adults of this family have mostly been collected during June (29%), July (25%), May (15%), August (14%), April (7%), and September (5%).

In 255 records from GBIF, this family has been collected at elevations ranging from 3 to 20669 ft, with an average (median) of 1881 ft.

Family Range

source

Map of specific collection sites

Specimens of the Caddisfly Family Glossosomatidae

1 Adult

Glossosoma (Little Brown Short-horned Sedge) Caddisfly Adult

1 Picture

Glossosoma (Glossosomatidae) (Little Brown Short-horned Sedge) Caddisfly Adult from the Big Thompson River in Montana

Collected March 12, 2010 from the Big Thompson River in Montana

Added by Bnewell on June 26, 2011

Collected March 12, 2010 from the Big Thompson River in Montana and added by Bnewell on June 26, 2011

2 Male Adults

Male Glossosoma (Little Brown Short-horned Sedge) Caddisfly Adult

9 Pictures

Lateral view of a Male Glossosoma (Glossosomatidae) (Little Brown Short-horned Sedge) Caddisfly Adult from the Cedar River in Washington

Key characteristics verified under the microscope:
-The head has 3 ocelli.
-Maxillary palp has 5 segments, with the second segment rounded. In some of the pictures it looks like 6 with the 3rd segment rounded, but the basal "segment" in that case isn't part of the palp.
-Foretibiae lack preapical spurs.
-Pronotum with mesal setose warts widely spaced.

All of this very clearly indicates Glossosomatidae. Beyond there:

-The tibial spur counts (fore / middle / hind tibiae) are 2, 4, and 4.
-From the pictures, the hind wing discoidal cell is closed, not open. Subfamily Glossosomatinae.
-The upper and lower parts of the mesepisternum are separated by a constriction, not a transverse suture. Microscope picture included.

This leads to a very confident genus ID of Glossosoma. I don't have the information to take it to species.

Collected July 1, 2021 from the Cedar River in Washington

Added by Troutnut on July 4, 2021

Collected July 1, 2021 from the Cedar River in Washington and added by Troutnut on July 4, 2021

Male Glossosoma alascense (Saddle-case Maker) Caddisfly Adult

8 Pictures

Lateral view of a Male Glossosoma alascense (Glossosomatidae) (Saddle-case Maker) Caddisfly Adult from Rock Creek in Montana

I lost track of this specimen before I could get it under my microscope, but caddis expert Dave Ruiter was able to identify it from pictures as Glossosoma, with an uncertain suggestion of G. alascense as the most likely species.

Collected July 8, 2019 from Rock Creek in Montana

Added by Troutnut on July 18, 2019

Collected July 8, 2019 from Rock Creek in Montana and added by Troutnut on July 18, 2019

1 Larva

Glossosoma (Little Brown Short-horned Sedge) Caddisfly Larva

11 Pictures

Dorsal view of a Glossosoma (Glossosomatidae) (Little Brown Short-horned Sedge) Caddisfly Larva from the Yakima River in Washington

I caught this tiny larva without a case, but it seems to key pretty clearly to to Glossosomatidae. From there, the lack of sclerites on the mesonotum points to either Glossosoma or Anagapetus. Although it's difficult to see in a 2D image from the microscope, it's pretty clear in the live 3D view that the pronotum is only excised about 1/3 of its length to accommodate the forecoxa, not 2/3, which points to Glossosoma at Couplet 5 of the Key to Genera of Glossosomatidae Larvae.

Collected February 17, 2023 from the Yakima River in Washington

Added by Troutnut on February 20, 2023

Collected February 17, 2023 from the Yakima River in Washington and added by Troutnut on February 20, 2023

3 Underwater Pictures of Glossosomatidae Caddisflies:

View Fullsize

Three big Ephemerella subvaria mayfly nymphs share a rock with some cased caddis larvae.

In this picture: Mayfly Species Ephemerella subvaria (Hendrickson) and Caddisfly Genus Glossosoma (Little Brown Short-horned Sedge).

Taken March 19, 2004

Added by Troutnut on January 25, 2006

Taken March 19, 2004 and added by Troutnut on January 25, 2006

View Fullsize

In this picture: Caddisfly Genus Glossosoma (Little Brown Short-horned Sedge).

Taken September 19, 2006 from the East Branch of Trout Brook in New York

Added by Troutnut on October 4, 2006

Taken September 19, 2006 from the East Branch of Trout Brook in New York and added by Troutnut on October 4, 2006

View Fullsize

These are glossosomatids, Jason. They are probably Glossosoma nigrior, though it is possible that we are looking at mixed species. The ones to the right with their aggregate of similar sized grains are classic Glossosoma, while the ones to the left with the large anchor pebbles could possibly be Agapetus. Regardless, they're all commonly referred to as saddle case makers.

In this picture: Caddisfly Family Glossosomatidae (Saddle-case Maker).

Taken June 21, 2006 from Spring Creek in Wisconsin

Added by Troutnut on July 1, 2006

Taken June 21, 2006 from Spring Creek in Wisconsin and added by Troutnut on July 1, 2006

Discussions of Glossosomatidae

Glossosoma intermedium or nigrior

5 replies

Posted by Wiflyfisher on Jun 30, 2020 in the genus Glossosoma

Last reply on Jul 31, 2020 by Creno

Caught and photographed in the Upper Midwest on May 12, 2020. I resized my original photo for the website.

pupa color

7 replies

Posted by LittleJ on Apr 19, 2008 in the genus Glossosoma

Last reply on Apr 22, 2008 by LittleJ

I was thinking very dark olive w/a ginger shuck. Sound right to any of you?
thanks
jeff

Agapetus are EVERYWHERE!!!!

1 replies

Posted by Litobrancha on Apr 12, 2007

Last reply on Apr 12, 2007 by GONZO

Jason

just wanted to spread the word about agapetus. many trout streams have healthy populations of agapetus and there is no reason that some of these species are important to early season emerger/dry fly fishing. small (#18-22) black caddis dry or emerger patterns will mimic them nicely, as well as Dolophilodes Wormaldia and Chimarra.

my colleagues are describing 12 new species of agapetus, mostly from the southeastern united states. i would encourage troutnuts to attempt to collect and rear agapetus pupae. it is pretty easy to do, find pupating cases and remove them from the rocks using forceps and into a small jar of water. If you use a jar with a small amount of water (just a little bit more than required to cover the pupae, removing the small stones around the puparium), then they will pupate in a refrigerator (preferably 60 C or so). Leave the lid loose to allow oxygen to equilibrate with the pupae. This also works for Rhyacophila, which build a similar puparium. We are describing new species of both Agapetus and Rhyacophila and it would be great to have specimens from Troutnuts!!! if interested in doing this, and it is time, email me litobrancha@yahoo.com You can send them to me in alcohol, who knows what else is out there!!!!

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