Mayfly Family Isonychiidae (Slate Drakes)
Taxonomic Navigation -?-
Kingdom Animalia (Animals)
» Phylum Arthropoda (Arthropods)
» Class Insecta (Insects)
» Order Ephemeroptera (Mayflies)
» Family Isonychiidae (Slate Drakes)
| Genus in Isonychiidae |  |  |
| IsonychiaSlate Drakes | 20 | 105 |
Common Name
| Match | Common Name |
 | Slate Drakes |
20 Mayfly Specimens in the Family Isonychiidae:
Isonychia bicolor (Mahogany Dun) Mayfly Spinner
View 15 PicturesI got several really nice pictures of this spinner. I also collected a female on the same trip.
View 15 PicturesI got several really nice pictures of this spinner. I also collected a female on the same trip.Region: Northeast
Collected Aug 9, 2006
Added Aug 11, 2006
Isonychia bicolor (Mahogany Dun) Mayfly Dun
View 13 Pictures
View 13 PicturesRegion: Upper Midwest
Collected Jun 14, 2005
Added May 26, 2006
Isonychia bicolor (Mahogany Dun) Mayfly Nymph
View 7 PicturesThis Isonychia bicolor nymph from the Catskills displays the prominent white stripe sometimes characteristic of its species. This is the first such specimen I've photographed, because members of the same species in the Upper Midwest have a more subdued stripe (and were once thought to be a different species, Isonychia sadleri). The striking coloration on this eastern nymph is more appealing.
View 7 PicturesThis Isonychia bicolor nymph from the Catskills displays the prominent white stripe sometimes characteristic of its species. This is the first such specimen I've photographed, because members of the same species in the Upper Midwest have a more subdued stripe (and were once thought to be a different species, Isonychia sadleri). The striking coloration on this eastern nymph is more appealing.Region: Catskills
Collected Apr 19, 2006
Added Apr 21, 2006
5 Streamside Pictures of Isonychiidae Mayflies:
View Full Size
Several Isonychia bicolor nymphs had recently crawled out onto these rocks to emerge, leaving behind their telltale shucks (
Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.).
In this picture: Mayfly Species Isonychia bicolor (Mahogany Dun).
View Full SizeHere's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.
In this picture: Mayfly Species Isonychia bicolor (Mahogany Dun).
Closeup of some recently emerged Isonychia bicolor nymphs from a small stream.
In this picture: Mayfly Species Isonychia bicolor (Mahogany Dun).
In this picture: Mayfly Species Isonychia bicolor (Mahogany Dun).
Recent Discussions of Isonychiidae
Penns Creek Slate Draker's 4 Replies »
Penns is one of the few places where a #10 iso will nail em' all year long
ReplyIso 1 Reply »Posted by JMV on Sep 21, 2006 in the species Isonychia bicolor
Last reply on Sep 21, 2006 by Troutnut
Great site, I'm an Iso. fanatic... JM
ReplyAre Isonychia mayflies technically multibrooded? 2 Replies »Here's what I've written in my article on Isonychia about their hatching:
I'm curious if they can really be called multibrooded or not, since they don't produce more than one generation per year (as far as I know). They simply have distinct populations within the same generation which emerge at different times during the year. Does that count?
All my books are packed up in boxes right now so I don't have a technical definition of the term handy.
ReplySome Isonychia species are multibrooded, but not in the same way as most other multibrooded mayflies like the Baetidae. In those species, the flies emerging in midsummer or Fall are the offspring of the earlier hatch from the same year. In Isonychia, the Fall emergers are offspring from the previous Fall. They are present as half-grown nymphs when the first of their generation emerge. Although Isonychia broods have distinct peaks, some may be found on the water at any time in between.
I'm curious if they can really be called multibrooded or not, since they don't produce more than one generation per year (as far as I know). They simply have distinct populations within the same generation which emerge at different times during the year. Does that count?
All my books are packed up in boxes right now so I don't have a technical definition of the term handy.
There is 1 more topic.
New features!
