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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.

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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Mayfly Species Neoleptophlebia memorialis

This species produces sparse hatches.

The origin of the name of this species is interesting, as described in the original publication (Eaton 1884): "I have assigned another to this species, which has reference
to its original captor, whose untimely death was primarily due to exposure in the course of the expedition when the insect was obtained." It does not say who the captor was.

I guess mayfly collecting is dangerous business! That's especially true given that it would have been collected mid-summer, because the original description only included the male adult.

Where & when

Time of year : Late June to late July

In 3 records from GBIF, adults of this species have been collected during June (100%).

In 2 records from GBIF, this species has been collected at elevations of 3166 and 6535 ft.

Species Range

Hatching behavior

Time of day : Afternoon

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.

Male Spinner

Described in Needham et al (1935) as Paraleptophlebia pallipes
Body length: 6 mm
Wing length: 7 mm

This is a species with rather highly contrasting colors. Top of head and thorax are black, the tip of the abdomen is brown, the intervening part is white. The legs are pale brownish with white tarsi. The wings are whitish, a little milky along the costa the entire length but more so in the region of the stigma, where cross veins are very obscure, few in number, straight and unbranched. The extreme wing base is tinged with brown.

Abdominal segments 3 to 6 are white with touches of brown on the border behind the spiracles and on the spiracles themselves. The ganglia show through and are yellow. Segment 2 is pale brown and 7 to 10 are darker.

The basal joint of the forceps is somewhat irregularly tapering to its apical 4th and then widened slightly to the tip. The 3rd segment is nearly as long as the 2nd but much more slender. The penes are separated by a goblet-shaped notch. The sperm duct ends in a slender terminal tube behind which externally stands a long, sharp, curving spine directed posteriorly, its length more than half the depth of the notch and its tip surpassing the tip of the sperm duct (see fig. 134).

Specimens of the Mayfly Species Neoleptophlebia memorialis

1 Male Spinner
1 Nymph

Start a Discussion of Neoleptophlebia memorialis

References

Mayfly Species Neoleptophlebia memorialis

Species Range
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