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.
Most physical descriptions on Troutnut are direct or slightly edited quotes from the original scientific sources describing or updating the species, although there may be errors in copying them to this website. Such descriptions aren't always definitive, because species often turn out to be more variable than the original describers observed. In some cases, only a single specimen was described! However, they are useful starting points.
Source: Epiproct And Dorsal Process Structure In The Allocapnia Forbesi Frison, Allocapnia Pygmaea (Burmeister), And Allocapnia Rickeri Frison Species Groups (Plecoptera: Capniidae), And Inclusion Of Allocapnia Minima (Newport) In A New Species Group
Male epiproct. Apical segment of upper limb ca. 316 - 322 µm long, armed on apical ca. 155 - 172 µm with dense patch of wave-like spikes (Figs. 61 - 63); apical segment ca. 120 - 148 µm wide at base, tapered to a bluntly rounded tip. Basal segment of upper limb ca. 421 µm long, and ca. 81 - 85 µm wide at mid-length; basal segment with a shallow, median groove. Greatest width of lower limb ca. 222 - 233 µm; lower limb bearing sparse, marginal row of long setae in apical third. Male tergal process. Prominent raised structures on abdominal terga 7 and 8 (Figs. 64 - 66). Tri-lobed process of tergum 8 ca. 153 - 200 µm wide, and bearing a broad, shallow notch, interrupted by a low median projection. Lobes of process appear slender and angled slightly forward in lateral aspect; surfaces covered with scale-like structures; anterior face bearing a transverse groove. Process of tergum 7 weakly tri-lobed, ca. 103 - 160 µm wide, and covered with scale-like structures.