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.
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I caught this tiny larva without a case, but it seems to key pretty clearly to to Glossosomatidae. From there, the lack of sclerites on the mesonotum points to either Glossosoma or Anagapetus. Although it's difficult to see in a 2D image from the microscope, it's pretty clear in the live 3D view that the pronotum is only excised about 1/3 of its length to accommodate the forecoxa, not 2/3, which points to Glossosoma at Couplet 5 of the Key to Genera of Glossosomatidae Larvae.
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True Bug Family Notonectidae (Backswimmers)
Backswimmers are often important to trout, especially in ponds. They're one of the insects which usually doesn't factor into a fly angler's decisions at all, but it pays to be aware of them because in just-so situations the trout eat nothing else.
Be careful handling them--they have a painful bite.
Be careful handling them--they have a painful bite.
Where & when
In 954 records from GBIF, adults of this family have mostly been collected during July (22%), August (17%), June (11%), September (10%), October (8%), April (8%), May (6%), and March (6%).
In 52 records from GBIF, this family has been collected at elevations ranging from 23 to 19685 ft, with an average (median) of 2382 ft.
Family Range
Egg-Laying behavior
The adults breathe air. Normally they rest upside down at the water's surface with part of their abdomen sticking up just out of the water to breathe, but they can dive for extended periods carrying an air bubble with them. They are able to leave the water and fly around.Nymph biology
Diet: Other insects, including other backswimmers
Specimens of Backswimmers:
2 Adults
Notonectdiae adults can leave the water and fly off whenever they wish. This specimen was caught when it landed on my car. These adults are one of the few aquatic insects that can protect itself with a strong beak.
Start a Discussion of Notonectidae
References
- Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.
True Bug Family Notonectidae (Backswimmers)
Taxonomy
3 genera (Buenoa, Martarega, and Notonecta) aren't included.