Troutnut.com Fly Fishing for Trout Home
User Password
or register.
Scientific name search:

Springflies and Yellow Stones

Scientific Name
MatchScientific Name
****Perlodidae

This common name refers to only one family.

Stonefly Family Perlodidae

These are pretty much always called Springflies and Yellow Stones.
This family contains some very important species inhabiting most freestone streams across the continent. They are often mistaken for early instar (Instar: Many invertebrates molt through dozens of progressively larger and better-developed stages as they grow. Each of these stages is known as an instar. Hard-bodied nymphs typically molt through more instars than soft-bodied larvae.) Perlidae (Golden Stones), which they closely resemble. The most notable differences between the two families are the perlodids much longer tails and antennae and usually more slender appearance. Their lack of obvious thoracic (Thorax: The thorax is the middle part of an insect's body, in between the abdomen and the head, and to which the legs and wings are attached.) gilling is another difference. The most important genus of the family, Isoperla, is the easiest to recognize with its longitudinally striped abdomens (though this is not a hard fast rule).

The family can be broken down into two groups:

The subfamily Isoperlinae, or Stripetails - contains five genera; three are monotypic (Monotypic: a taxonomic level containing a single lower level. Example - a genus consisting of a single species.), one has two species, and the very large and ubiquitous Isoperla genus containing most of the species anglers call Little Yellow Stones or Yellow Sallies. These are common hatches on our freestone streams during late spring and Summer.

The subfamily Perlodinae, or Springflies - contains thirty two genera in many sizes and colors including some important medium browns, yellows, and even some olives. It also includes the large Skwala Springflies of the West. As their group name implies, these are most common in the late winter through Spring.
Isogenoides hansoni (Appalachian Springfly) Stonefly NymphIsogenoides hansoni (Appalachian Springfly) Stonefly Nymph View 11 PicturesThis large Perlodidae stonefly was a strikingly bright yellow color, more so than any other insect I've seen. I didn't enhance it much. See the discussion threads to follow how we identified this specimen, which was listed incorrectly for several years.
Collected April 19, 2006 from in
Added to Troutnut.com by on April 21, 2006
Isoperla (Stripetails and Yellow Stones) Stonefly AdultIsoperla (Stripetails and Yellow Stones) Stonefly Adult View 10 PicturesSeveral stoneflies of this species were flying around a small stream last night. I tied on a brown drake imitation of about the right size/color to approximate these stones, and was rewarded with a hard-fighting 17-inch brown trout.
Collected July 7, 2006 from in
Added to Troutnut.com by on July 8, 2006
Top 10 Fly Hatches
Top Gift Shop Designs
Top Insect Specimens
Miscellaneous Sites