I can't take credit for this one. This caddisfly larva was found on Sunday by my friend who lives in Sugar Hollow in a spring seep on her land: all of the photos are hers. It's a new taxon to add to our EPT list, something that's "rare," and from what I can tell it has not been found before this in the state of Virginia (see: http://eol.org/data_objects/14881240). It is listed as "vulnerable" in North Carolina.
Limnephilidae (Northern case-maker), Pseudostenophylax sparsus. This is a species that, according to Beaty, "occurs in seeps and temporary streams" ("The Trichoptera of North Carolina," p. 84). According to Wiggins, "the larvae live in cool spring runs or small streams of intermittent flow; they burrow into sand and gravel substrate as water recedes and presumably are protected there until the return of surface water." (Larvae of the North American Caddisfly Genera, First Edition, 1977, p.278.) This one was found, quoting my friend, in a "little spring that emerges from an iron pipe in the ravine near our upper garden." She adds that "this pipe comes out of a wall (constructed of cement blocks more than 100 years ago), feeds into small spring pool (in photo below). Water flows from it after heavy or prolonged rainfall. Thus it may be dry for more than 1/2 of the year."
For the genus ID, let's go to Beaty. "Mesonotum with pair of plates with as (sic.) [all] setal areas confluent; row of metanotal setae between sa2 and sa3; lateral humps without sclerites; abdominal gills single; head and thorax uniformly orangish to yellowish brown with pale muscle scars." (p. 84) (Wiggins, p. 278, says much the same thing.)
1. The color of the head and pronotum and the pale muscle scars are clear in the photo above.
2. The "confluent setal areas" (i.e. setae run from sa1 to sa2 to sa3) show up pretty well in this photo.
3. And the metanotal setal row between the sa2 sclerites is very clear here.
3. The left lateral hump can be seen in the following photo, though it is difficult in this shot to see if there may or may not be any sclerites.
4. On the abdominal gills -- they are single, but we don't have a photo. This insect was not preserved: it was returned to the spring. But my friend had a clear view of the gills when the larva crawled far enough out of its case. It just didn't stay out long enough to get a picture.
I don't see any reason to doubt this identification, and it is, indeed, a significant find. I normally skip over spring seeps when I'm out looking for insects, but that's about to change.
When Wiggins was writing in 1977, two species of Pseudostenophylax were said to exist in the Eastern U.S. -- P. uniformis and P. sparsus (p. 278). But according to Beaty (p. 84) "Pseudostenophylax uniformis is now considered a subspecies of P. sparsus." In some sources, by the way, it is called Pseudosteonophylax sparsus uniformis.
Late addition: While sorting through the vials in my own Limnephilid collection, I found one marked "Pseudostenophylax": it contains two larvae I had collected in spring 2010 in the "bio-blitz" at Patricia Byrom Park. P. sparsus for sure! Here are two microscope photos: 1) the single gills on the abdominal segments, and 2) another look at the setal rows on the meso and metanota.
Taihao le 太好了 the Chinese would say. "Too much!"
Late correction: P. sparsus was reported from Giles, Greene, Madison, Page, and Rappahannock counties in 2008 by Flint. "In Virginia it has been taken mostly in the northern Blue Ridge in and near Shenandoah National Park." Oliver S. Flint, Jr., Richard L. Hoffman, Charles R. Parker, "An Annotated List of the Caddisflies (Trichoptera) of Virginia: Part II. Families of Integripalpia," Banisteria, Number 31 (2008), p. 16.