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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
Blue-winged Olives

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

Artistic view of a Perlodidae (Springflies and Yellow Stones) Stonefly Nymph from the Yakima River in Washington
This one seems to lead to Couplet 35 of the Key to Genera of Perlodidae Nymphs and the genus Isoperla, but I'm skeptical that's correct based on the general look. I need to get it under the microscope to review several choices in the key, and it'll probably end up a different Perlodidae.
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.
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Stonefly Species Allocapnia granulata (Little Snowflies)

Where & when

This is the most abundant eastern member of the Capniidae family.

In 119 records from GBIF, adults of this species have mostly been collected during February (26%), January (24%), March (24%), December (12%), and April (11%).

In 6 records from GBIF, this species has been collected at elevations ranging from 125 to 3593 ft, with an average (median) of 2690 ft.

Species Range

Physical description

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: The Winter Stoneflies (Plecoptera: Capniidae) Of Mississippi

Male tergal process. Tergum 8 process deeply notched in dorsal aspect, forming a pair of elongate knobs in V-shaped pattern (Fig. 14); knobs armed with scale-like tubercles and an additional small, hairy scale-less knob is located behind larger scaled knobs. In lateral aspect, scaled knobs are low at anterior margin and are slanted upward toward projecting, hairy, posterior knobs (Fig. 15).

Female subgenital plate. Abdominal sternum 8 bears a slightly projecting median plate with low mesal point and base constricted by small lateral notches (Figs. 16, 60). Sterna 7 and 8 completely separated by membrane.

Source: New Records Of Winter Stoneflies (Plecoptera: Capniidae) In Mississippi

Discussions of Allocapnia granulata

Little Black Stonefly pics
12 replies
Posted by Adirman on Apr 14, 2018
Last reply on Apr 21, 2018 by Martinlf
Hey guys, went out on the Neversink for awhile today and had a look around, saw a lot of little dark flies, may be the little black stone fly? Hard to tell cuz looked like Caddis too. Looks like about a size 16? Any pics of available of this species would be great.


Start a Discussion of Allocapnia granulata


Stonefly Species Allocapnia granulata (Little Snowflies)

Species Range
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